Kelly's first four test grades of the period were 80, 72, 96, and 88. Which inequality represents the grades she can
earn on the fifth test to have a test average of no less than 80?
V
O gs16
O 92 16
O g564
O 9264
Answer: option D on edge 2020
Step-by-step explanation:
if you reverse the formula for mean, then you just insert the numbers and you have your answer
What is the greatest common factor of the polynomial below?
20x^3 - 14x
Answer:
the correct answer is 2x
Answer:
D. 2x
Step-by-step explanation:
20x² : 1, 2, 4, 5, 10, 20, x
14x : 1, 2, 7, 14, x
The greatest common factor of the polynomial is 2x.
2x(10x² - 7)
How do you write 89,700,000,000 in scientific notation? ___× 10^____
Answer:
It's written as
[tex]89.7 \times {10}^{9} [/tex]
Or
[tex]8.97 \times {10}^{10} [/tex]
Hope this helps you
Answer:
8.97 * 10 ^10
Step-by-step explanation:
We want one nonzero digit to the left of the decimal
8.97
We moved the decimal 10 places to the left
The exponent is positive 10 since we moved 10 places to the left
8.97 * 10 ^10
A square has a perimeter of 12x+52 units. Which expression represents the side leagth of the square in units
Answer:
12x/2 or 52/2
Step-by-step explanation:
Ok, perimeter is length+length+width+width. 12x/2 and 52/2 could are probably the answers.
F (X) = x² - 2x and 6(x) = 3x+1
A) Find F(g(-4))
B) Find F(g(x)) simply
C) find g^-1 (x)
Answer: See bolded below
Step-by-step explanation:
With the given f(x) and g(x) given, we can directly plug them in to solve. The inverse is to replace the y with x and x with y, then solve for y.
A. f(g(-4))=143
g(-4)=3(-4)+1
g(-4)=-12+1
g(-4)=-11
With g(-4), we plug that into f(x) to find f(g(-4)).
f(-11)=(-11)²-2(-11)
f(-11)=121+22
f(-11)=143
------------------------------------------------------------------------------------
B. 9x²-1
(3x+1)²-2(3x+1)
(9x²+6x+1)-6x-2
9x²-1
------------------------------------------------------------------------------------
C. g⁻¹(x)=(x-1)/3
x=3y+1
x-1=3y
(x-1)/3=y
Thomas Kratzer is the purchasing manager for the headquarters of a large insurance company chain with a central inventory operation. Thomas's fastest-moving inventory item has a demand of 6,100 units per year. The cost of each unit is $101, and the inventory carrying cost is $8 per unit per year. The average ordering cost is $31 per order. It take about 5 days for an order to arrive, and the demand for 1 week is 120 units. (This is a corporate operation, and the are 250 working days per year.)A) What is the EOQ?B) What is the average inventory if the EOQ is used?C) What is the optimal number of orders per year?D) What is the optimal number of days in between any two orders?E) What is the annual cost of ordering and holding inventory?F) What is the total annual inventory cost, including cost of the 6,100 units?
Answer and Step-by-step explanation:
The computation is shown below:
a. The economic order quantity is
[tex]= \sqrt{\frac{2\times \text{Annual demand}\times \text{Ordering cost}}{\text{Carrying cost}}}[/tex]
[tex]= \sqrt{\frac{2\times \text{6,100}\times \text{\$31}}{\text{\$8}}}[/tex]
= 217 units
b. The average inventory used is
[tex]= \frac{economic\ order\ quantity}{2}[/tex]
[tex]= \frac{217}{2}[/tex]
= 108.5 units
c. The optimal order per year
[tex]= \frac{annual\ demand}{economic\ order\ quantity}[/tex]
[tex]= \frac{6,100}{217}[/tex]
= 28 orders
d. The optima number of days is
[tex]= \frac{working\ days}{optimal\ number\ of\ orders}[/tex]
[tex]= \frac{250}{28}[/tex]
= 8.9 days
e. The total annual inventory cost is
= Purchase cost + ordering cost + carrying cost
where,
Purchase cost is
[tex]= \$6,100 \times \$101[/tex]
= $616,100
Ordering cost = Number of orders × ordering cost per order
= 28 orders × $31
= $868
Carrying cost = average inventory × carrying cost per unit
= 108.50 units × $8
= $868
So, the total would be
= $616,100 + $868 + $868
= $617,836
Help with one integral problem?
Answer: [tex]2\sqrt{1+tant}+C[/tex]
Step-by-step explanation:
To integrate means to find the antiderivative of the function. For this problem, we can use u-substitution.
[tex]\int\limits {\frac{dt}{cos^2t\sqrt{1+tant} } } \[/tex]
Let's first use our identities to rewrite the function. Since [tex]\frac{1}{cosx} =secx[/tex], we can use this identity.
[tex]\int\limits {\frac{sec^2t}{\sqrt{1+tant} } } \,[/tex]
[tex]u=\sqrt{1+tant}[/tex]
[tex]du=\frac{sec^2t}{2\sqrt{1+tant} } dt[/tex]
Now that we have u and du, we can plug them back in.
[tex]\int\limits {2} \, du[/tex]
[tex]\int\limits{2} \, du=2u[/tex]
Since we know u, we can plug that in.
[tex]2\sqrt{1+tant}[/tex]
This may seem like the correct answer, but we forgot to add the constant.
[tex]2\sqrt{1+tant}+C[/tex]
The hypotenuse of a right triangle is 10 cm long. One of the triangle’s legs is 3
times the length of the other leg. Find the lengths of the two legs of the
triangle. Round to the nearest tenth if necessary
Answer:
one side is [tex]\sqrt{10}[/tex] and other 3[tex]\sqrt{10}[/tex]
in decimal one side = 3.16
other side = 9.48
Step-by-step explanation:
In right angle
if two sides containing right angle is a and b and h is hypotenuse then
by Pythagoras theorem
a^2 + b^2 = h^2
__________________________________
let one side be x
given
One of the triangle’s legs is 3 times the length of the other leg
then other leg = 3x
given h = 10 cm
applying Pythagoras theorem
[tex]a^2 + b^2 = h^2\\x^2 + (3x)^2 = 10^2\\x^2 + 9x^2 = 100\\10x^2 = 100\\x^2 = 100/10 = 10\\x = \sqrt{10}[/tex]
Thus, one side is [tex]\sqrt{10}[/tex] and other 3[tex]\sqrt{10}[/tex]
[tex]\sqrt{10} = 3.16\\[/tex]
thus, in decimal one side = 3.16
other side = 3.16*3 = 9.48
Solve by completing the square. x2−12x=−27 Select each correct answer. −9 −3 3 9 15
Answer:
x=9,3
Step-by-step explanation:
x²-12x=-27
x²-12x+(12/2)²=-27+(12/2)²
x²-12x+6²=-27+36
(x-6)²=9
x-6=[tex] \frac{ + }{ - } \sqrt{9} [/tex]
x-6=+3 and x-6=-3
x=9 and 3
AT&T would like to test the hypothesis that the proportion of 18- to 34-year-old Americans that own a cell phone is less than the proportion of 35- to 49-year-old Americans. A random sample of 200 18- to 34-year-old Americans found that 126 owned a smartphone. A random sample of 175 35- to 49-year-old Americans found that 119 owned a smartphone. If Population 1 is defined as 18- to 34-year-old Americans and Population 2 is defined as 35- to 49-year-old Americans, the correct hypothesis statement for this hypothesis test would be
Answer:
The null and alternative hypothesis can be written as:
[tex]H_0: \pi_1-\pi_2=0\\\\H_a:\pi_1-\pi_2< 0[/tex]
Step-by-step explanation:
This is a hypothesis test for the difference between proportions.
The claim is that the proportion of 18- to 34-year-old Americans that own a cell phone is less than the proportion of 35- to 49-year-old Americans.
This claim will be reflected in the alternnative hypothesis, that will state that the population proportion 1 (18 to 34) is significantly smaller than the population proportion 2 (35 to 49).
On the contrary, the null hypothesis will state that the population proportion 1 is ot significantly smaller than the population proportion 2.
Then, the null and alternative hypothesis can be written as:
[tex]H_0: \pi_1-\pi_2=0\\\\H_a:\pi_1-\pi_2< 0[/tex]
The significance level is assumed to be 0.05.
The sample 1, of size n1=200 has a proportion of p1=0.63.
[tex]p_1=X_1/n_1=126/200=0.63[/tex]
The sample 2, of size n2=175 has a proportion of p2=0.68.
[tex]p_2=X_2/n_2=119/175=0.68[/tex]
The difference between proportions is (p1-p2)=-0.05.
[tex]p_d=p_1-p_2=0.63-0.68=-0.05[/tex]
The pooled proportion, needed to calculate the standard error, is:
[tex]p=\dfrac{X_1+X_2}{n_1+n_2}=\dfrac{126+119}{200+175}=\dfrac{245}{375}=0.653[/tex]
The estimated standard error of the difference between means is computed using the formula:
[tex]s_{p1-p2}=\sqrt{\dfrac{p(1-p)}{n_1}+\dfrac{p(1-p)}{n_2}}=\sqrt{\dfrac{0.653*0.347}{200}+\dfrac{0.653*0.347}{175}}\\\\\\s_{p1-p2}=\sqrt{0.001132+0.001294}=\sqrt{0.002427}=0.049[/tex]
Then, we can calculate the z-statistic as:
[tex]z=\dfrac{p_d-(\pi_1-\pi_2)}{s_{p1-p2}}=\dfrac{-0.05-0}{0.049}=\dfrac{-0.05}{0.049}=-1.01[/tex]
This test is a left-tailed test, so the P-value for this test is calculated as (using a z-table):
[tex]\text{P-value}=P(z<-1.01)=0.1554[/tex]
As the P-value (0.1554) is bigger than the significance level (0.05), the effect is not significant.
The null hypothesis failed to be rejected.
There is not enough evidence to support the claim that the proportion of 18- to 34-year-old Americans that own a cell phone is less than the proportion of 35- to 49-year-old Americans.
The tread life of a particular brand of tire is normally distributed with mean 60,000 miles and standard deviation 3800 miles. Suppose 35 tires are randomly selected for a quality assurance test. Find the probability that the mean tread life from this sample of 35 tires is greater than 59,000 miles. You may use your calculator, but show what you entered to find your answer. Round decimals to the nearest ten-thousandth (four decimal places).
Answer:
P [ x > 59000} = 0,6057
Step-by-step explanation:
We assume Normal Distribution
P [ x > 59000} = (x - μ₀ ) /σ/√n
P [ x > 59000} = (59000 - 60000)/ 3800
P [ x > 59000} = - 1000/3800/√35
P [ x > 59000} = - 1000*5,916 /3800
P [ x > 59000} = - 5916/3800
P [ x > 59000} = - 1,55
We look for p value for that z score n z-table and find
P [ x > 59000} = 0,6057
Una persona se dirige a un edificio y observa lo alto del mismo con un ángulo de elevación “x”, después de caminar 10m observa al mismo punto anterior con ángulo de elevación “y”, si la altura del edificio es de 30m. Calcule: "3Tgx.Ctgy + Tgx"
Answer:
3
Step-by-step explanation:
To begin with notice that
[tex]\displaymode{ \tan(x) = \frac{30}{10 + 30\cot(y)} }[/tex]
From that equation you get that
10 tan(x) + 30tan(x) cot(x) = 30
therefore
tan(x) + 3 tan(x) cot(x) = 3
If Q(x) = x2 – X – 2, find Q(-3).
Answer:
10
Step-by-step explanation:
for this you need to sub the value of -3 for x
Q(-3)=(-3)^2-(-3)-2
=9+3-2
=10
Answer:
Q= x - X/x - 2/x
Step-by-step explanation:
hope this helps !
Write the equation of a line that goes through point (0, -8) and has a slope of 0
Answer:
Step-by-step explanation:
y + 8 = 0(x - 0)
y + 8 = 0
y = -8
The table shows three unique functions. (TABLE IN PIC) Which statements comparing the functions are true? Select three options. Only f(x) and h(x) have y-intercepts. Only f(x) and h(x) have x-intercepts. The minimum of h(x) is less than the other minimums. The range of h(x) has more values than the other ranges. The maximum of g(x) is greater than the other maximums.
Answer:
(A)Only f(x) and h(x) have y-intercepts.
(C)The minimum of h(x) is less than the other minimums.
(E)The maximum of g(x) is greater than the other maximums.
Step-by-step explanation:
From the table
f(0)=0 and h(0)=0, therefore, Only f(x) and h(x) have y-intercepts. (Option A)
Minimum of f(x)=-14Minimum of g(x)=1/49Minimum of h(x)=-28Therefore, the minimum of h(x) is less than the other minimums. (Option C).
Maximum of f(x)=14
Maximum of g(x)=49
Maximum of h(x)=0
Therefore, the maximum of g(x) is greater than the other maximums. (Option E)
Answer: It's B,C, and E
Step-by-step explanation:
What is the value of 500$ invested at 4% interest compounded annually for 7 years
Answer:
657.96
Step-by-step explanation:
use formula A=P(1+r/n)^nt
A=500(1+.04/1)^1*7
A=500(1.04)^7
A=500(1.3159~)
A= 657.96~
WILL GIVE BRAINLIEST What is the perimeter of the track, in meters? Use π = 3.14 and round to the nearest hundredth of a meter. plz help me
Answer:
P ≈ 317.08 m
Step-by-step explanation:
Circumference: C = πd
Step 1: Find circumference of both domes
C = π(50)
Since it's a dome, we divide by 2
50π/2 = 25π
Since we have 2 domes, we simply multiply by 2 again
25π(2) = 50π
Step 2: Find perimeter of track
50π + 80(2)
P = 50π + 160
P = 317.08 m
Given that a function, h, has a domain of -3 ≤ x ≤ 11 and a range of 1 ≤ h(x) ≤ 25 and that h(8) = 19 and h(-2) = 2, select the statement that could be true for h
Answer:
C
Step-by-step explanation:
We know that A is not true because we know that h(8) is 19, not 21. B is also not true because the value of h(x) can't be -1. D can't be true because x can't be 13, therefore the answer is C.
There are 3 times as many novels as comic books in a bookstore.If there are 2480 books altogether, how many comic books are there in the bookstore.
Answer:
620 comic books
2480 / 4 is 620.
620 x 3 is 1860.
1860 + 620 is 2480.
Done!
Before the pandemic cancelled sports, a baseball team played home games in a stadium that holds up to 50,000 spectators. When ticket prices were set at $12, the average attendance was 30,000. When the ticket prices were on sale for $10, the average attendance was 35,000.
(a) Let D(x) represent the number of people that will buy tickets when they are priced at x dollars per ticket. If D(x) is a linear function, use the information above to find a formula for D(x). Show your work!
(b) The revenue generated by selling tickets for a baseball game at x dollars per ticket is given by R(x) = x-D(x). Write down a formula for R(x).
(c) Next, locate any critical values for R(x). Show your work!
(d) If the possible range of ticket prices (in dollars) is given by the interval [1,24], use the Closed Interval Method from Section 4.1 to determine the ticket price that will maximize revenue. Show your work!
Optimal ticket price:__________ Maximum Revenue:___________
Answer:
(a)[tex]D(x)=-2,500x+60,000[/tex]
(b)[tex]R(x)=60,000x-2500x^2[/tex]
(c) x=12
(d)Optimal ticket price: $12
Maximum Revenue:$360,000
Step-by-step explanation:
The stadium holds up to 50,000 spectators.
When ticket prices were set at $12, the average attendance was 30,000.
When the ticket prices were on sale for $10, the average attendance was 35,000.
(a)The number of people that will buy tickets when they are priced at x dollars per ticket = D(x)
Since D(x) is a linear function of the form y=mx+b, we first find the slope using the points (12,30000) and (10,35000).
[tex]\text{Slope, m}=\dfrac{30000-35000}{12-10}=-2500[/tex]
Therefore, we have:
[tex]y=-2500x+b[/tex]
At point (12,30000)
[tex]30000=-2500(12)+b\\b=30000+30000\\b=60000[/tex]
Therefore:
[tex]D(x)=-2,500x+60,000[/tex]
(b)Revenue
[tex]R(x)=x \cdot D(x) \implies R(x)=x(-2,500x+60,000)\\\\R(x)=60,000x-2500x^2[/tex]
(c)To find the critical values for R(x), we take the derivative and solve by setting it equal to zero.
[tex]R(x)=60,000x-2500x^2\\R'(x)=60,000-5,000x\\60,000-5,000x=0\\60,000=5,000x\\x=12[/tex]
The critical value of R(x) is x=12.
(d)If the possible range of ticket prices (in dollars) is given by the interval [1,24]
Using the closed interval method, we evaluate R(x) at x=1, 12 and 24.
[tex]R(x)=60,000x-2500x^2\\R(1)=60,000(1)-2500(1)^2=\$57,500\\R(12)=60,000(12)-2500(12)^2=\$360,000\\R(24)=60,000(24)-2500(24)^2=\$0[/tex]
Therefore:
Optimal ticket price:$12Maximum Revenue:$360,000Abox in the shape of a rectangular prism, with dimensions 12 inches by 18 inches by 12 inches, can hold exactly 12
cubes measuring 6 inches on each side.
If the length and width of the base are doubled, how many cubes could the new box hold?
18
0 24
48
o 96
Answer:
48
Step-by-step explanation:
You are doubling 2 dimensions, so you just multiply the volume by 2 each time. Since you are doing it twice, you multiply the volume by 4. 12*4=48. You could also brute force it and just do 24*36*12/216(the volume of the 6 inch cube).
Given that, a box in the shape of a rectangular prism, with dimensions 12 inches by 18 inches by 12 inches, can hold exactly 12 cubes measuring 6 inches on each side.
We need to find that how many cubes it holds if the length and width of the base are doubled,
We know that,
Volume of a rectangular prism = length × width × height
Volume of the new rectangular prism, = 2length × 2width × height
= 4(length × width × height)
= 4(12·12·18)
= 4×2592
= 10,368
Volume of the cube = side³
= 6³ = 216
The number of cube that the new rectangular prism can hold = Volume of the rectangular prism / Volume of the cube
= 10,368 / 216
= 48
Hence, the new rectangular prism, can hold 48 cubes.
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Ava's bacteria population is modeled by an equation. Chase models his bacteria
population with a graph. Ava says that on day 14, she will have more bacteria than Chase
Is she right? Why or why not?
Answer:
P(Chase) > P(Ava)
700 > 587
Therefore, Ava's claim is wrong!
On day 14, Chase's bacteria population will be greater than Ava's bacteria population.
Step-by-step explanation:
Please refer to the attached image.
Ava's bacteria population is modeled by the following equation.
[tex]$ b(t) = 200(1+0.08)^t $[/tex]
Where t is time in days and b(t) is the population of the bacteria after t days.
The graph represents the population of Chase's bacteria.
Ava claims that on day 14, she will have more bacteria than Chase.
Let us compare the population of both bacteria.
Chase bacteria population when t = 14 days:
From the graph, the population is approximately 700 at t = 14 days
P(Chase) ≈ 700
Ava bacteria population when t = 14 days:
at t = 14 days
[tex]b(t) = 200(1+0.08)^t \\\\ b(14) = 200(1.08)^{14} \\\\ b(14) = 200 (2.93719)\\\\ b(14) = 587.44[/tex]
So, the population is approximately 587 at t = 14 days
P(Ava) ≈ 587
P(Chase) > P(Ava)
700 > 587
Therefore, Ava's claim is wrong!
On day 14, Chase's bacteria population will be greater than Ava's bacteria population.
Answer:
D
Step-by-step explanation:
Trust
the length of a rectangular sheet of metal is 9.96m and it's breadth is 5.08m. Find the area of the metal.Correct the answer to 2 significant figures and then correct the answer to 0.1 meter square
Answer:
The area of the sheet is approximately 50.59 m² or 50.6 m²
Step-by-step explanation:
The area of a rectangle is given by the following expression:
[tex]area = width*height[/tex]
Since breadth is the same as the width of the sheet, we can calculate its area as shown below:
[tex]area = 9.96*5.08 = 50.59[/tex]
The area of the sheet is approximately 50.59 m² or 50.6 m²
Rachel measures the lengths of a random sample of 100 screws. The mean length was 2.6 inches, with a standard deviation of 1.0 inches. Using the alternative hypothesis (µ < µ0), Rachel found that a z-test statistic was equal to -1.25. What is the p-value of the test statistic? Answer choices are rounded to the thousandths place.
Answer:
Step-by-step explanation:
Using the alternative hypothesis (µ < µ0),
To find the p-value with test statistic -1.25 and assuming a standard level of significance of 0.05, using a p value calculator, the p-value is 0.1057 which is great that 0.05. Thus, the results is not significant.
Using the p value calculation.
1. Check the left tailed z table as the test statistic is negative,
2. Then find the probabilitythat z is greater than your test statistic (look up your test statistic on the z-table- the value under 1.2 and 0.05 which is 0.8944
3. Then, find its corresponding probability, and subtract it from 1 to get your p-value- 1-0.8944 = 0.1056.
Find the slope-intercept form of the line with slope 6 that passes through the point (3,5).
Answer:
y=6x-13
Step-by-step explanation:
Since we are given a point and a slope, we can use the slope intercept formula.
[tex]y-y_{1} = m(x-x_{1} )[/tex]
where (x1, y1) is a point and m is the slope.
We know that the slope is 6 and the point is (3,5). Therefore,
x1= 3
y1= 5
m=6
Substitute these into the formula.
[tex]y-5 = 6(x-3 )[/tex]
Distribute the 6. Multiply each term inside the parentheses by the number outside the parentheses.
[tex]y-5= (6*x) + (6*-3)[/tex]
[tex]y-5=6x-18[/tex]
We want to find the slope-intercept form, or y=mx+b. Therefore, we must get y by itself.
5 is being subtracted from y. The inverse of subtraction is addition. Add 5 to both sides.
[tex]y-5+5=6x-18+5[/tex]
[tex]y= 6x-18+5[/tex]
[tex]y= 6x -13[/tex]
What is 200 percent of (0.020(5/4) + 3 ((1/5) - (1/4)))
Answer:
0.1/4-3/20=1/40-6/40=-1/8 200% of this is -1/4
Step-by-step explanation:
This shows that 200 percent of (0.020(5/4) + 3 ((1/5) - (1/4))) is -2.75
Given the expression as shown in the question:
[tex]200\% \ of \ [0.020(\frac{5}{4} )+3(\frac{1}{5}- \frac{1}{4} )][/tex]
Expand the expression in the square bracket using the distribution law as shown:
[tex]=200\% \ of \ [0.020(\frac{5}{4} )+3(\frac{4-5}{20} )]\\=200\% \ of \ [0.020(\frac{5}{4} )+3(\frac{-1}{20} )]\\=200\% \ of \ [0.020(\frac{5}{4} )-(\frac{3}{20} )]\\=200\% \ of \ [0.020(1.25 )-\frac{3}{20}]\\=\frac{200}{100} \times [0.025-0.15]\\=2 \times [-0.125]\\=-2.75[/tex]
Hence the correct answer to the expression is -2.75.
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A travel agent is booking trips for tourists who travel from New York to Chicago. Tourists have three choices for how to travel from New York to Chicago. They can take an airplane for $350, a bus for $150, or a train for $225. Once they arrive in Chicago, they can travel by van to their hotel for $60 or take a cab for $40. If each option is equally likely to occur, what is the probability that a tourist will spend more than $275 on these 2 legs of the trip?
Answer:
P = 1/2
Step-by-step explanation:
If the tourist spends more than 275$, they must not arrive in Chicago by bus.
( 150 + 60 < 275, 150 + 40 < 275)
The total options the tourist can make:
3 x 2 = 6
(1st leg: 3 possible options, 2nd leg: 2 possible options)
The number of options the tourist can make after excluding bus option:
2 x 2 = 4
(1st leg: 2 remaining possible options, 2nd leg: 2 possible options)
The number of options the tourist can make after excluding the bus option and spend more than 275$:
4 - 1 = 3
(excluding the case of selecting train and cab, because 225 + 40 < 275)
=> The probability that the tourist will spend more than 275$ on these 2 legs of the trip:
P = 3/6 = 1/2
Probability helps us to know the chances of an event occurring. The probability that a tourist will spend more than $275 on these 2 legs of the trip is 0.5.
What is Probability?Probability helps us to know the chances of an event occurring.
[tex]\rm Probability=\dfrac{Desired\ Outcomes}{Total\ Number\ of\ outcomes\ possible}[/tex]
Given that Tourists have three choices for how to travel from New York to Chicago. They can take an aeroplane for $350, a bus for $150, or a train for $225. Also, when they arrive in Chicago, they can travel by van to their hotel for $60 or take a cab for $40. Therefore, the cost of different routes is,
Aeroplane($350) + Van($60) = $410Aeroplane($350) + Cab($40) = $390Bus($150) + Van($60) = $210Bus($150) + Cab($40) = $190Train($225) + Van($60) = $285Train($225) + Cab($40) = $265As it can be seen that there are 3 cases where a tourist will spend more than $275, while the total number of cases is 6. Therefore, the probability that a tourist will spend more than $275 on these 2 legs of the trip is,
Probability = 3/6 = 1/2 =0.5z
Hence, the probability that a tourist will spend more than $275 on these 2 legs of the trip is 0.5.
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Reliance on solid biomass fuel for cooking and heating exposes many children from developing countries to high levels of indoor air pollution. The article "Domestic Fuels, Indoor Air Pollution, and Children's Health" (Annals of the N.Y. Academy of Sciences, 2008: 209-217) pm-tented information on various pulmonary characteristics in samples of children whose households in India used either biomass fuel or liquefied petroleum gas (LPG). For the 755 children in biomass households, the sample mean peak expiratory flow (a person's maximum speed of expiration) was 3.30 Us, and the sample standard deviation was 1.20. For the 750 children whose households used liquefied petroleum gas, the sample mean PEF was 4.25 and the sample standard deviation was 1.75.
a. Calculate a confidence interval at the 95% confidence level for the population mean PEF for children in biomass households and then do likewise for children in LPG households. What is the simultaneous confidence level for the two intervals?
b. Carry out a test of hypotheses at significance level .01 to decide whether true average PEF is lower for children in biomass households than it is for children in LPG households (the cited article included a P-value for this test).
c. FEV1, the forced expiratory volume in 1 second, is another measure of pulmonary function. The cited article reported that for the biomass households the sample mean FEY, was 2.3 L/s and the sample standard deviation was .5 L/s. If this information is used to compute a 95% CI for population mean FEV1, would the simultaneous confidence level for this interval and the first interval calculated in (a) be the same as the simultaneous confidence level deter-mined there? Explain.
Answer:
A) 95% confidence interval for the population mean PEF for children in biomass households = (3.214, 3.386)
95% confidence interval for the population mean PEF for children in LPG households
= (4.125, 4.375)
Simultaneous confidence interval for both = (3.214, 4.375)
B) The result of the hypothesis test is significant, hence, the true average PEF is lower for children in biomass households than it is for children in LPG households.
C) 95% confidence interval for the population mean FEY for children in biomass households = (2.264, 2.336)
Simultaneous confidence interval for both = (2.264, 4.375)
This simultaneous interval cannot be the same as that calculated in (a) above because the sample mean obtained for children in biomass households here (using FEY) is much lower than that obtained using PEF in (a).
Step-by-step explanation:
A) Confidence Interval for the population mean is basically an interval of range of values where the true population mean can be found with a certain level of confidence.
Mathematically,
Confidence Interval = (Sample mean) ± (Margin of error)
Margin of Error is the width of the confidence interval about the mean.
It is given mathematically as,
Margin of Error = (Critical value) × (standard Error of the mean)
Critical value will be obtained using the z-distribution. This is because although, there is no information provided for the population standard deviation, the sample sizes are large enough for the sample properties to approximate the population properties.
Finding the critical value from the z-tables,
Significance level for 95% confidence interval
= (100% - 95%)/2 = 2.5% = 0.025
z (0.025) = 1.960 (from the z-tables)
For the children in the biomass households
Sample mean = 3.30
Standard error of the mean = σₓ = (σ/√N)
σ = standard deviation of the sample = 1.20
N = sample size = 755
σₓ = (1.20/√755) = 0.0436724715 = 0.04367
95% Confidence Interval = (Sample mean) ± [(Critical value) × (standard Error of the mean)]
CI = 3.30 ± (1.960 × 0.04367)
CI = 3.30 ± 0.085598
95% CI = (3.214402, 3.385598)
95% Confidence interval = (3.214, 3.386)
For the children in the LPG households
Sample mean = 4.25
Standard error of the mean = σₓ = (σ/√N)
σ = standard deviation of the sample = 1.75
N = sample size = 750
σₓ = (1.75/√750) = 0.063900965 = 0.063901
95% Confidence Interval = (Sample mean) ± [(Critical value) × (standard Error of the mean)]
CI = 4.25 ± (1.960 × 0.063901)
CI = 4.25 ± 0.125246
95% CI = (4.12475404, 4.37524596)
95% Confidence interval = (4.125, 4.375)
Simultaneous confidence interval for both = (3.214, 4.375)
B) The null hypothesis usually goes against the claim we are trying to test and would be that the true average PEF for children in biomass households is not lower than that of children in LPG households.
The alternative hypothesis confirms the claim we are testing and is that the true average PEF is lower for children in biomass households than it is for children in LPG households.
Mathematically, if the true average PEF for children in biomass households is μ₁, the true average PEF for children in LPG households is μ₂ and the difference is μ = μ₁ - μ₂
The null hypothesis is
H₀: μ ≥ 0 or μ₁ ≥ μ₂
The alternative hypothesis is
Hₐ: μ < 0 or μ₁ < μ₂
Test statistic for 2 sample mean data is given as
Test statistic = (μ₂ - μ₁)/σ
σ = √[(s₂²/n₂) + (s₁²/n₁)]
μ₁ = 3.30
n₁ = 755
s₁ = 1.20
μ₂ = 4.25
n₂ = 750
s₂ = 1.75
σ = √[(1.20²/755) + (1.75²/750)] = 0.07740
z = (3.30 - 4.25) ÷ 0.07740 = -12.27
checking the tables for the p-value of this z-statistic
Significance level = 0.01
The hypothesis test uses a one-tailed condition because we're testing in only one direction.
p-value (for z = -12.27, at 0.01 significance level, with a one tailed condition) = < 0.000000001
The interpretation of p-values is that
When the p-value > significance level, we fail to reject the null hypothesis and when the p-value < significance level, we reject the null hypothesis and accept the alternative hypothesis.
Significance level = 0.01
p-value = 0.000000001
0.000000001 < 0.01
Hence,
p-value < significance level
This means that we reject the null hypothesis, accept the alternative hypothesis & say that true average PEF is lower for children in biomass households than it is for children in LPG households.
C) For FEY for biomass households,
Sample mean = 2.3 L/s
Standard error of the mean = σₓ = (σ/√N)
σ = standard deviation = 0.5
N = sample size = 755
σₓ = (0.5/√755) = 0.0182
95% Confidence Interval = (Sample mean) ± [(Critical value) × (standard Error of the mean)]
CI = 2.30 ± (1.960 × 0.0182)
CI = 2.30 ± 0.03567
95% CI = (2.264, 2.336)
Simultaneous confidence interval for both = (2.264, 4.375)
This simultaneous interval cannot be the same as that calculated in (a) above because the sample mean obtained for children in biomass households here (using FEY) is much lower than that obtained using PEF in (a).
Hope this Helps!!!
There are (7^13)^3 x 7^0 strawberries in a field . What is the total number of strawberries in the field
Answer:
Step-by-step explanation:
[tex]7^{0}=1[/tex]
[tex](7^{13})^{3}*7^{0}=7^{13*3}*1\\\\=7^{39}[/tex]
Jacqueline and Maria set up bug barns to catch lady bugs. Jacqueline caught ten more than three times the number of lady bugs that Maria caught. If c represents the number of lady bugs Maria caught, write an expression for the number of lady bugs that Jacqueline caught.
Answer:
(CX3)+10
Step-by-step explanation:
Answer:
c×3+10= j
Step-by-step explanation: