I need help plz someone help me solved this problem I need help ASAP! I will mark you as brainiest!
Answers
Answer: (a) [tex]\bold{A=900\bigg(1+\dfrac{0.07}{4}\bigg)^{4t}}[/tex]
(b) A = $1680.67
(c) t = 9.99 years
(d) A = $1689.85
Step-by-step explanation:
[tex]A=P\bigg(1+\dfrac{r}{n}\bigg)^{nt}[/tex] where
A is the amount accrued (balance)P is the principal (original/initial amount)r is the interest rate (convert to a decimal)n is the number of times compounded per yeart is the number of yearsa) Given: P = 900, r = 7% = 0.07, n = quarterly = 4
[tex]\bold{A=900\bigg(1+\dfrac{0.07}{4}\bigg)^{4t}}[/tex]
b) Given: P = 900, r = 7% = 0.07, n = quarterly = 4, t = 9
[tex]A=900\bigg(1+\dfrac{0.07}{4}\bigg)^{4(9)}\\\\\\A = 900\bigg(1+\dfrac{0.07}{4}\bigg)^{36}[/tex]
A = 1680.67
c) Given: A = 1800, P = 900, r = 7% = 0.07, n = quarterly = 4
[tex]1800=900\bigg(1+\dfrac{0.07}{4}\bigg)^{4t}\\\\\\2=\bigg(1+\dfrac{0.07}{4}\bigg)^{4t}\\\\\\ln\ 2=ln\bigg(1+\dfrac{0.07}{4}\bigg)^{4t}\\\\\\ln\ 2 = 4t\ ln\bigg(1+\dfrac{0.07}{4}\bigg)\\\\\\\dfrac{ln\ 2}{4\ ln\bigg(1+\dfrac{0.07}{4}\bigg)}=t\\\\\\\bold{t=9.99}[/tex]
d) [tex]A=Pe^{rt}[/tex]
Given: P = 900, r = 7% = 0.07, t = 9
[tex]A=900e^{0.07(9)}\\\\\\A=900e^{.63}\\\\\\\bold{A=1689.85}[/tex]
Related Questions
According to a recent study, some experts believe that 15% of all freshwater fish in a particular country have such high levels of mercury that they are dangerous to eat. Suppose a fish market has 150 fish we consider randomly sampled from the population of edible freshwater fish. Use the Central Limit Theorem (and the Empirical Rule) to find the approximate probability that the market will have a proportion of fish with dangerously high levels of mercury that is more than two standard errors above 0.15. You can use the Central Limit Theorem because the fish were randomly sampled; the population is more than 10 times 150; and n times p is 22.5, and n times (1 minus p) is 127.5, and both are more than 10.
Answers
Answer:
The approximate probability that the market will have a proportion of fish with dangerously high levels of mercury that is more than two standard errors above 0.15 is 0.95.
Step-by-step explanation:
According to the Central limit theorem, if from an unknown population large samples of sizes n > 30, are selected and the sample proportion for each sample is computed then the sampling distribution of sample proportion follows a Normal distribution.
The mean of this sampling distribution of sample proportion is:
[tex]\mu_{\hat p}=0.15[/tex]
The standard deviation of this sampling distribution of sample proportion is:
[tex]\sigma_{\hat p}=\sqrt{\frac{p(1-p)}{n}}[/tex]
As the sample size is large, i.e. n = 150 > 30, the central limit theorem can be used to approximate the sampling distribution of sample proportion by the normal distribution.
Compute the mean and standard deviation as follows:
[tex]\mu_{\hat p}=0.15\\\\\sigma_{\hat p}=\sqrt{\frac{p(1-p)}{n}}=\sqrt{\frac{0.15(1-0.15)}{150}}=0.0292[/tex]
So, [tex]\hat p\sim N(0.15, 0.0292^{2})[/tex]
In statistics, the 68–95–99.7 rule, also recognized as the empirical rule, is a shortcut used to recall that 68%, 95% and 99.7% of the Normal distribution lie within one, two and three standard deviations of the mean, respectively.
Then,
P (µ-σ < X < µ+σ) ≈ 0.68
P (µ-2σ <X < µ+2σ) ≈ 0.95
P (µ-3σ <X < µ+3σ) ≈ 0.997
Then the approximate probability that the market will have a proportion of fish with dangerously high levels of mercury that is more than two standard errors above 0.15 is 0.95.
That is:
[tex]P(\mu_{\hat p}-2\sigma_{\hat p}<\hat p<\mu_{\hat p}+2\sigma_{\hat p})=0.95\\\\P(0.15-2\cdot0.0292<\hat p<0.15+2\cdot0.0292)=0.95\\\\P(0.092<\hat p<0.208)=0.95[/tex]
Find the vector x determined by the given coordinate vector [x]B and the given basis B.
B = {[1 -3 1], [-3 8 3],[8 -2 3]}, [x]_B = [-3 -2 3]
a. [9 -13 0]
b. [0 -6 21]
c. [13 -24 -2]
d. [3 -13 16]
Answers
How do you write 0.0683 in scientific notation? ____× 10^____
Answers
Answer:
It's written as
[tex]6.83 \times {10}^{ - 2} [/tex]
Hope this helps you
Answer:
6.83 × 10 -2
hopefully this helped :3
can someone help me with this please???
Answers
Answer:
Lateral surface area would be (13*4)*2 + (4*4)*2 = (52*2) + (16*2) = 104 + 32 = 136 units^2.
Surface area would be 136 + 104 = 240 units^2.
Step-by-step explanation:
I hope this helps you!
Denise is planning to put a deck in her back yard. The deck will be a 10-by-7-foot rectangle with a semicircle of diameter 4 feet, as shown below. Find the area of the deck (in square feet).(round your answer to two decimal places)
Answers
Answer:
[tex]approx. = 85.28 {ft}^{2} [/tex]
Step-by-step explanation:
You can think of this as adding the area of the rectangular portion of the deck (length x width) and the semicircular portion (πr^2)/2.
(l×w)+(πr^2)/2
(10×7)+((π2^2)/2
79+2π
[tex]approx. = 85.28 {ft}^{2} [/tex]
A restaurant has a main location and a traveling food truck. The first matrix A shows the number of managers and associates employed. The second matrix B shows the average annual cost of salary and benefits (in thousands of dollars). Complete parts (a) through (c) below.
Managers Associates
Restaurant 5 25 = A
Food Truck 1 4
Salary Benefits
Managers 41 6 = B
Associates 20 2
a. Find the matrix product AB .
b. Explain what AB represents.
c. According to matrix AB , what is the total cost of salaries for all employees (managers and associates) at the restaurant? What is the total cost of benefits for all employees at the food truck?
Answers
Answer:
A*B= [tex]\left[\begin{array}{cc}705&80\\121&14 \end{array}\right][/tex]
Step-by-step explanation:
Given A= [tex]\left[\begin{array}{cc}5&25\\1&4\end{array}\right] \left[\begin{array}{cc}41&6\\20&2\end{array}\right][/tex] = B
Finding A*B means multiplying the first row with the first column and first row with the second column would give the first row elements. The second ro0w elements are obtained by multiplying the second row with the 1st column and second row with the second column.
so A*B= [tex]\left[\begin{array}{cc}5*41+ 25*20&5*6 + 25*2\\ 1*41+4*20 & 1*6+ 4*2\end{array}\right][/tex]
Now multiply and add the separate elements of the matrix A*B=
[tex]\left[\begin{array}{cc}205+500&30+50\\41+80&6+8\end{array}\right][/tex]
A*B= [tex]\left[\begin{array}{cc}705&80\\121&14 \end{array}\right][/tex]
b. The 1st element of the 1st row shows the salaries of the managers and 2nd element of the 1st row the salaries of associates at the restaurant . The second row 1 st element shows the benefits of the managers and 2nd element the benefits of the associates at the food truck.
c. The total cost of salaries for all employees (managers and associates) at the restaurant = 705 + 80 = 785
Total cost of benefits for all employees at the food truck= 121 + 14= 135
Find the critical value z Subscript alpha divided by 2 that corresponds to the confidence level 90%.
Answers
Answer:
,.........................................................
by how much is 25% of #25 greater than 15% of #15
Answers
Answer:
4
Step-by-step explanation:
25% of 25
0.25 × 25 = 6.25
15% of 15
0.15 × 15 = 2.25
Find the difference.
6.25 - 2.25
= 4
A simple random sample of 20 items resulted in a sample mean of 10. The population standard deviation is = 3. Round your answers to two decimal places.
a. What is the standard error of the mean, ?
b. At 95% confidence, what is the margin of error?
Answers
Answer:
a. 0.67
b. 1.31
Step-by-step explanation:
We have the following information n = 20, mean (m) = 10 and standard deviation (sd) = 3
a.
SE (m) = sd / n ^ (1/2)
replacing we have:
SE (m) = 3/20 ^ (1/2) = 0.67
Therefore the standard error of the mean is 0.67
b.
the critical value is obtained as shown below:
the level of sifnificance is alfa = 1 - 0.95 = 0.05
the critical value with level of significance alfa / 2 = 0.05 / 2 = 0.025
and to this value corresponds z = 1.96 (z table)
The margin of error with 95 confidence is calculated as follows:
E = z * SE
E = 1.96 * 0.67
E = 1.31
Therefore the margin of error is 1.31
(a) The standard error will be "0.67".
(b) The margin of error will be "1.31".
According to the question,
Standard deviation,
sd = 3Sample size,
n = 20(a)
As we know,
→ The Standard error,
= [tex]\frac{sd}{\sqrt{n} }[/tex]
= [tex]\frac{3}{\sqrt{20} }[/tex]
= [tex]0.67[/tex]
(b)
As we know,
→ The margin of error,
= [tex]Z_{a/2}\times \frac{sd}{\sqrt{n} }[/tex]
By substituting the values, we get
= [tex]Z_{a/2}\times \frac{3}{\sqrt{20} }[/tex]
= [tex]1.96\times 0.67[/tex]
= [tex]1.31[/tex]
Thus the above response is right.
Learn more:
https://brainly.com/question/10501147
Write a two column proof Given: AB || DC; BC || AE Prove: BC/EA = BD/EB
Answers
Answer:
Step-by-step explanation:
Given:
AB║DC and BC║AE
To prove:
[tex]\frac{\text{BC}}{\text{EA}}=\frac{\text{BD}}{\text{EB}}[/tex]
Statements Reasons
1). ∠ABE ≅ ∠CDB 1). Alternate interior angles
2). ∠AEB ≅ ∠CBD 2). Alternate interior angles
3). ΔCBD ~ ΔAEB 3). AA property of similarity
4). [tex]\frac{\text{BC}}{\text{EA}}=\frac{\text{BD}}{\text{EB}}[/tex] 4). Property of similarity [Corresponding sides of two similar triangles are proportional]
Christopher collected data from a random sample of 800 voters in his state asking whether or not they would vote to reelect the current governor. Based on the results, he reports that 54% of the voters in his city would vote to reelect the current governor. Why is this statistic misleading?
Answers
Answer:
The statistic is misleading because Christopher collects his sample from a population (voters in his state) and make inferences about another population (voters in his city).
Step-by-step explanation:
The statistic is misleading because Christopher collects his sample from a population (voters in his state) and make inferences about another population (voters in his city).
He should make inferences about the population that is well represented by his sample (voters in his state), or take a sample only from voters from his city to make inferences about them.
A furniture store has set aside 800 square feet to display its sofas and chairs. Each sofa utilizes 50 sq. ft. and each chair utilizes 30 sq. ft. At least five sofas and at least five chairs are to be displayed.
a. Write a mathematical model representing the store's constraints.
b. Suppose the profit on sofas is $200 and on chairs is $100. On a given day, the probability that a displayed sofa will be sold is 0.03 and that a displayed chair will be sold is 0.05. Mathematically model each of the following objectives:
1. Maximize the total pieces of furniture displayed.
2. Maximize the total expected number of daily sales.
3. Maximize the total expected daily profit.
Answers
Answer:
a) 50S + 30C ≤ 800
b) 1) MAX = S + C
2) Max = 0.03S + 0.05C
3) Max = 6S + 5C
Step-by-step explanation:
Given:
Total space = 800 square feet
Each sofa = 50 square feet
Each chair = 30 square feet
At least 5 sofas and 5 chairs are to be displayed.
a) Write a mathematical model representing the store's constraints:
Let S denote number of sofas displayed and C denote number of chairs displayed.
The mathematical model will be:
50S + 30C ≤ 800
At least 5 sofas are to be dispayed: S ≥ 5
At least 5 chairs are to be displayed: C ≥ 5
b)
1) Maximize the total pieces of furniture displayed:
S + C = MAX
2) Maximize the total expected number of daily sales:
MAX = 0.03S + 0.05C
3) Maximize the total expected daily profit:
Given:
Profit on sofas = $200
Profit on chairs = $100
Max Expected daily profit =
Max = (200S * 0.03) + (100C * 0.05)
Max = 6S + 5C
3. A 12 % discount on a pair of washer and dryer that Gayle purchased, amounted to $156.00.
Calculate the net price.
Answers
Answer:
For this case we know that the price after the 12% of discount is 156 and we want to findd the net price so then we can use the following proportional rule:
[tex] \frac{x}{100} = \frac{156}{100-12}[/tex]
Where x represent the net price. And if we solve for the value of x we got:
[tex] x= 100 *\frac{156}{88}= 177.273[/tex]
So then the net price for this case would be $ 177.273
Step-by-step explanation:
For this case we know that the price after the 12% of discount is 156 and we want to findd the net price so then we can use the following proportional rule:
[tex] \frac{x}{100} = \frac{156}{100-12}[/tex]
Where x represent the net price. And if we solve for the value of x we got:
[tex] x= 100 *\frac{156}{88}= 177.273[/tex]
So then the net price for this case would be $ 177.273
Find the slope-intercept form of the line through (6, – 3) and perpendicular to the line y = 3x – 5.
Answers
Answer:
y=-1/3x-1
Step-by-step explanation:
We have the information y=3x-5, the lines are perpendicular, and the new line passes through (6,-3). The slopes of perpendicular lines are negative reciprocals so you need to find the negative reciprocal of 3, so flip it to 1/3 and multiply by -1, we get the slope of the new line as -1/3. So far we have the equation y=-1/3x+b. We are given a point on the line, (6,-3), so we can plug these into the equation as x and y to solve for the y-intercept, b. You set it up as -3=-1/3(6)+b. First you multiply to get -3=-2+b, then you add 2 to both sides to isolate the variable and you get b=-1. Then you can use b to complete your equation with y=-1/3x-1.
An adult has a total of about 22.5 square feet (ft2) of skin. Use the fact that 1 m is approximately equal to 3.281 feet to convert this measurement to square meters (m2). Round your answer to the nearest hundredth. Do not type the units in the space below.
Answers
Answer:
There are about 3.281 * 3.281 = 10.764 square feet in one square meter. Therefore, 22.5 square feet is 22.5 / 10.764 = 2.09 square meters.
Working together, Edith and Rupert can pick 3 quarts of blueberries in an
hour. How many quarts can they pick in 7 hours?
Answers
Answer:
21
Step-by-step explanation:
Multiply 3 quarts to 7 hours
Which is 21
Mark me as brainliest
Step-by-step explanation:
Edith picks 3
Rupert picks 3
3 + 3 = 6 quarts of blueberries in 1 hour
6 blueberries = 1 hour
x. =. 7 hours
x = 7 hours ÷ 1 hour × 6 blueberries
x =. 42 quarts of blueberries
Find the percent of increase. Original Price: $200 Retail Price: $250
Answers
Answer:
The percent of increase is 25%
Step-by-step explanation:
Percentage increase = increase in price/original price × 100 = ($250 - $200)/$200 × 100 = $50/$200 × 100 = 25%
HELP PLEASE!!!! I NEED HELP ASAP Which statement best describes the expression 3 + y ÷ 2? The quotient of 2 and the sum of 3 and y The quotient of the sum of 3 and y, and 2 The sum of 3 and the quotient of 2 and y The sum of 3 and the quotient of y and 2
Answers
Answer:
I believe it is D
Answer:
The sum of 3 and the quotient of y and 2.
Step-by-step explanation:
The order of operations requires that you evaluate the expression ...
3 + y ÷ 2
by first performing the division, then the addition. So, the addition gives you the sum of 3 and a quotient, because the quotient must be evaluated first.
The quotient is of y and 2 (not 2 and y), because the wording "the quotient of a and b" is always interpreted to mean a÷b.
So, the expression can be described as ...
the sum of 3 and the quotient of y and 2.
calculate find the area f a rectangle measuring 25 feet long by 8 feet wide
Answers
Answer: 200 ft²
Step-by-step explanation:
The area of a rectangle is length times width
So, simply do 25 * 8 = 200
Hey there! :)
Answer:
A = 200 ft².
Step-by-step explanation:
Use the formula A = l × w to determine the area of a rectangle:
A = 25 × 8
Multiply:
A = 200 ft².
What is a quadrilateral and give ten examples
Answers
Answer:
A quadralateral is any shape that has 4 sides ...
Step-by-step explanation:
rectangle
square
rhombus
Answer: A quadrilateral is a two dimensional shape(closed) with four sides.
Step-by-step explanation: The sides do not have to be equal.
Square
Rectange
Trapazoid
Diamond
Any four sided shape. They will classify as a quadrilateral as long as two of the shapes are not the same.
Past studies have indicated that the percentage of smokers is estimated to be about 35%. Given the new smoking cessation programs that have been implemented, you now believe that the percentage of smokers has reduced. a) If you going to test this claim at the 0.05 significance level, what would be your null and alternative hypotheses
Answers
Answer:
H0: p = 3.5
H1: p < 3.5
Step-by-step explanation:
We are told that past studies have indicated that the percentage of smokers is estimated to be about 35%, but with the new smoking cessation programs that have been implemented, it is believed that the percentage of smokers has been reduced, we must propose our null and alternative hypotheses, which would be the following:
Null hypothesis: H0: p = 3.5
Alternative hypothesis: H1: p < 3.5
1. Which of these is a Pythagorean triple?
(a) (3, 4, 5)
(b) (5, 6, 7)
(c) (10, 11, 12)
(d) (15, 16, 17)
2. If y2 = 172 – 82. What is the value of y?
(a) 10
(b) 25
(c) 15
(d) 16
3. How many kilograms are there in 5 tonnes?
(a) 500 kg
(b) 50 000 kg
(c) 5, 000 kg
(d) 50 kg
4. If the probability that a girl win a race is 0.6. What is the probability that that the girl loses the race?
(a) 0.4
(b) 1
(c) 4
(d) 6
5. The distance from Lagos to Ibadan can be measured using which of the following units of measurement?
(a) centimeter
(b) Millimeter
(c) Kilograms
(d) Kilometer
6. The longest side of a right-angled triangle is called?
(a) right side
(b) Opposite
(c) Hypotenuse
(d) None of the above
7. The mass/weight of your pen can be measured using………
(a) Grams
(b) Kilometer
(c) Centimetre
(d) Tonne
8. There 5 blue balls, 8 red balls and 2 black balls in a basket. One ball is picked at random. Find the probability that the ball picked is red.
(a) 58
(b) 815
(c) 215
(d) 13
9. The mass of a lorry can be measured using which of the following?
(a) liter
(b) Kilometer
(c) Tonne
(d) Milligram
10. How many tonnes are there in 15 000 kg?
(a) 150 tonnes
(b) 15 tonnes
(c) 1500 tonnes
(d) 1.5 tonnes
11. What is 20% of #38 000?
(a) #7 600
(b) #3 800
(c) #2 800
(d) #760
12. Express 17:30 hours as a.m. or p.m. time.
(a) 7:30 pm
(b) 7:30 a.m.
(c) 5:30 p.m.
(d) 5:30 a.m.
13. Angle 900 is also called?
(a) left angle
(b) quarter angle
(c) right angle
(d) middle angle
14. “Kilo” is a Greek word from the word “khilioi” meaning what?
(a) Million
(b) Thousand
C) Billion
D) Hundred
15. Which is the most widely used system of measurement in the world?
(a) tape rule system
(b) counter system
(c) metric system
(d) none of the above
PART B
ANSWER ALL QUESTIONS
1. The largest unit of measurement for distance/length is kilometer. True or false …………………….
2. The probability that a student fails an examination is 0.2. What is the probability that the student passes the examination? .................
The members of a village cooperative agree to contribute time and money towards a one year village improvement programme (VIP). Below is the table of activities of the programme.
Activity
Time (hour)
Money(#)
Planting/ watering trees
300
20 000
Collecting/burning rubbish
200
0
Clearing storm ditches
80
5 000
Making speed bumps
20
5 000
3. How much is the total money pledged? …………..
4. Which activity takes more money? ………………..
5. Which activity cost no money? ……………………….
Answers
Answer
1. (a) (3,4,5)--3^2 +4^2=9+16=25=5^2
2. (b) 25--172-82=50/2=25
3. (c) 5,000 kg--1,000 kg in 1 tonne
4. (a) 0.4--1-0.6=0.4
5. (d) kilometer
6. (c) hypotenuse
7. (a) grams
8. i think it is (a) 58--5+8+2=15~~8/15 =0.53~closest answer is 58
9. (c) tonne
10. (b) 15 tonnes--1000 kg in 1 tonne
11. (a) #7,600--38000*20%, or 0.20, =7,600
12. (a) 7:30 pm
13. (c) right angle
(c) metric system
Part B
1. True
2. 0.8
3. 30,000 dollars--20,000 +0+5,000+5,000=30,000
4. Planting/watering trees--20 dollars
5. Collecting/burning rubbish--0 dollars
I NEED HELP FAST, THANKS! :)
Answers
Answer:
33 units²
Step-by-step explanation:
A (graphing) calculator shows you that f(4) ≈ 8, and f(8) ≈ 8.5. The curve is almost a straight line between, so the area is approximately ...
A = (1/2)(8 + 8.5)(4) = 33
__
If you do the integration, it gets a bit messy.
[tex]\displaystyle\dfrac{5}{7}\int_4^8{x^{2/7}}\,dx+\dfrac{1}{2}\int_4^8{x^{4/9}}\,dx+\int_4^8{6}\,dx\\\\=\left.\left(\dfrac{5}{9}x^{9/7}+\dfrac{9}{26}x^{13/9}+6x\right)\right|_4^8\approx 33.16[/tex]
The appropriate answer choice is 33 square units.
Which equation can be used to find the area of the rectangle? A. A=9+4 B. A=1/2 (9)(4) C. A=9+9+4+4 D. A=(9)(4)
Answers
Answer:
D. A=(9)(4)
Step-by-step explanation:
area= length x width = 9x4
Is (0,-2) a solution of 3x - y = 2?
Answers
Answer:
yes, (0,-2) is the answer when graphing this equation.
Step-by-step explanation:
Answer:
yes.
Step-by-step explanation:
3
Select the correct answer.
What are the solutions to this equation?
16x² + 9 = 25
Answers
Answer:
Step-by-step explanation:
16x^2 + 9 = 25
16x^2 = 16
x^2 = 1
x = 1, -1
help help help help pls
Answers
Hi !!
For f(x) = 3/x + 4 , B is correct.
• f(-3) = 3/(-3) + 4
f(-3) = - 1 + 4
f(-3) = 3
• f(-2) = 3/(-2) + 4
f(-2) = -1,5 + 4
f(-2) = 2,5
• f(1) = 3/(1) + 4
f(1) = 3 + 4
f(1) = 7
• f(2) = 3/(2) + 4
f(2) = 1,5 + 4
f(2) = 5,5
• f(3) = 3/(3) + 4
f(3) = 1 + 4
f(3) = 5
The length of a rectangle is seven times its width. The area of the rectangle is 175 square centimeters. Find the dimensions of the rectangle.
Answers
Answer:
The length is 35cmThe width is 5cmStep-by-step explanation:
Area of a rectangle = l × w
where
l is the length
w is the width
The length is seven times the width is written as
l = 7w
Area of the rectangle = 175 cm²
7w × w = 175
7w² = 175
Divide both sides by 7
w² = 25
Find the square root of both sides
w = √25
w = 5cm
But l = 7w
l = 7(5)
l = 35cm
The length is 35cm
The width is 5cm
Hope this helps you.
. The client was hoping for a likability score of at least 5.2. Use your sample mean and standard deviation identified in the answer to question 1 to complete the following table for the margins of error and confidence intervals at different confidence levels. Note: No further calculations are needed for the sample mean. (6 points: 2 points for each completed row) Confidence Level | Margin of error | Center interval | upper interval | Lower interval 68 95 99.7
Answers
Answer:
The 68% confidence interval is (6.3, 6.7).
The 95% confidence interval is (6.1, 6.9).
The 99.7% confidence interval is (5.9, 7.1).
Step-by-step explanation:
The Central Limit Theorem states that if we have a population with mean μ and standard deviation σ and take appropriately huge random-samples (n ≥ 30) from the population with replacement, then the distribution of the sample-means will be approximately normally distributed.
Then, the mean of the sample means is given by,
[tex]\mu_{\bar x}=\bar x[/tex]
And the standard deviation of the sample means (also known as the standard error)is given by,
[tex]\sigma_{\bar x}=\frac{\sigma}{\sqrt{n}} \ \text{or}\ \frac{s}{\sqrt{n}}[/tex]
The information provided is:
[tex]n=400\\\\\bar x=6.5\\\\s=4[/tex]
As n = 400 > 30, the sampling distribution of the sample-means will be approximately normally distributed.
(a)
Compute the 68% confidence interval for population mean as follows:
[tex]CI=\bar x\pm z_{\alpha/2}\cdot \frac{s}{\sqrt{n}}[/tex]
[tex]=6.5\pm 0.9945\cdot \frac{4}{\sqrt{400}}\\\\=6.5\pm 0.1989\\\\=(6.3011, 6.6989)\\\\\approx (6.3, 6.7)[/tex]
The 68% confidence interval is (6.3, 6.7).
The margin of error is:
[tex]MOE=\frac{UL-LL}{2}=\frac{6.7-6.3}{2}=0.20[/tex]
(b)
Compute the 95% confidence interval for population mean as follows:
[tex]CI=\bar x\pm z_{\alpha/2}\cdot \frac{s}{\sqrt{n}}[/tex]
[tex]=6.5\pm 1.96\cdot \frac{4}{\sqrt{400}}\\\\=6.5\pm 0.392\\\\=(6.108, 6.892)\\\\\approx (6.1, 6.9)[/tex]
The 95% confidence interval is (6.1, 6.9).
The margin of error is:
[tex]MOE=\frac{UL-LL}{2}=\frac{6.9-6.1}{2}=0.40[/tex]
(c)
Compute the 99.7% confidence interval for population mean as follows:
[tex]CI=\bar x\pm z_{\alpha/2}\cdot \frac{s}{\sqrt{n}}[/tex]
[tex]=6.5\pm 0.594\cdot \frac{4}{\sqrt{400}}\\\\=6.5\pm 0.392\\\\=(5.906, 7.094)\\\\\approx (5.9, 7.1)[/tex]
The 99.7% confidence interval is (5.9, 7.1).
The margin of error is:
[tex]MOE=\frac{UL-LL}{2}=\frac{7.1-5.9}{2}=0.55[/tex]
y=x2+3x+1 has how many real roots?
Answers
Answer:
2
Step-by-step explanation:
we will find the discriminant of the equation
d = b^2 - 4ac (here, a = 1 , b = 3 , c = 1. from the general formula: ax^2 + bx + c)
d = 9 - 4
d = 5
since d > 0, the roots are real and different
hence, the both the roots of this equation are equal