Answer:
The feature that makes the sample representative of the population is the choice of the contact mode (telephone landline or cellular phone line) with proportions representative of the ages of the subjects to be represented.
Step-by-step explanation:
The feature that makes the sample representative of the population is the choice of the contact mode (telephone landline or cellular phone line) with proportions representative of the ages of the subjects to be represented.
Older people tend to manage with landline phones, while younger people tend to have no landline phones but cell phone. Both groups must be proportionally represented to be representative of an adult population (18 years or older).
Vitamin D is important for the metabolism of calcium and exposure to sunshine is an important source of vitamin D. A researcher wanted to determine whether osteoperosis was associated with a lack of exposure to sunshine. He selected a sample of 250 women with osteoperosis and an equal number of women without osteoperosis. The two groups were matched - in other words they were similar in terms of age, diet, occupation, and exercise levels. Histories on exposure to sunshine over the previous twenty years were obtained for all women. The total number of hours that each woman had been exposed to sunshine in the previous twenty years was estimated. The amount of exposure to sunshine was compared for the two groups. Group of answer choices
Answer:
The type of observational study describer here is retrospective study.
Step-by-step explanation:
The complete question is:
Vitamin D is important for the metabolism of calcium and exposure to sunshine is an important source of vitamin D. A researcher wanted to determine whether osteoperosis was associated with a lack of exposure to sunshine. He selected a sample of 250 women with osteoperosis and an equal number of women without osteoperosis. The two groups were matched - in other words they were similar in terms of age, diet, occupation, and exercise levels. Histories on exposure to sunshine over the previous twenty years were obtained for all women. The total number of hours that each woman had been exposed to sunshine in the previous twenty years was estimated. The amount of exposure to sunshine was compared for the two groups. Determine what type of observational study is described. Explain.
Solution:
In retrospective study design, the concerned outcome has previously taken place in each participant by the phase he or she is signed up for the study, and the information are gathered either from past data or by requesting the participants to recall exposures.
It is also known as a historic cohort study.
A retrospective study is completed as posterior experiment, using data on events that have already taken place in the history. In most cases some or most of the data has already been collected and stowed in the archive.
In the provided scenario, the researcher collect the past data for the exposure to sunshine over the previous twenty years for 250 women. And estimated the total number of hours that each woman had been exposed to sunshine in the previous twenty years.
Then the researcher compares the amount of exposure to sunshine for the two groups.
Thus, the type of observational study describer here is retrospective study.
A student walk 60m on a bearing
of 028 degree and then 180m
due east. How is she from her
starting point, correct to the
nearest whole number?
Answer:
d = 234.6 m
Step-by-step explanation:
You can consider a system of coordinates with its origin at the beginning of the walk of the student.
When she start to walk, she is at (0,0)m. After her first walk, her coordinates are calculated by using the information about the incline and the distance that she traveled:
[tex]x_1=60cos28\°=52.97m\\\\y_1=60sin28\°=28.16m[/tex]
she is at the coordinates (52.97 , 28.16)m.
Next, when she walks 180m to the east, her coordinates are:
(52.97+180 , 28.16)m = (232.97 , 28.16)m
To calculate the distance from the final point of the student to the starting point you use the Pythagoras generalization for the distance between two points:
[tex]d=\sqrt{(x-x_o)^2+(y-y_o)^2}\\\\x=232.97\\\\x_o=0\\\\y=28.16\\\\y_o=0\\\\d=\sqrt{(232.97-0)^2+(28.16-0)^2}m=234.6m[/tex]
The displacement of the student on her complete trajectory was of 234.6m
The local food pantry has 1, 600 cans of fruit. They give away 155 cans of fruit each week. Assuming no new donations are made,
how many cans of fruit will remain after 6 weeks?
The solution is
What is the answer for this problem?
Answer:
670 Cans of fruit will be left
Step-by-step explanation:
First you multiply 155 by the 6 weeks.
That equals 930 and then you subtract 930 from 1,600 and that gives you 670.
There are 670 cans of fruit that will remain after 6 weeks the answer is 670 cans.
What is a sequence?It is defined as the systematic way of representing the data that follows a certain rule of arithmetic.
We have:
The local food pantry has 1, 600 cans of fruit. They give away 155 cans of fruit each week.
First term a = 1600
Common difference d = -155
After 6 weeks means on week 7.
n = 7
a(7) = 1600 + (7-1)(-155)
a(7) = 1600 - 930
a(7) = 670
Thus, there are 670 cans of fruit that will remain after 6 weeks the answer is 670 cans.
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Leah has 28 more marbles than Dan. 1/3 of Leah’s marbles are equal in number to 4/5 of Dan’s marbles. Find the number of marbles Leah has.
Answer:
48
Step-by-step explanation:
L = D + 28
⅓L = ⅘D
Solve the system of equations using elimination or substitution. Using substitution:
⅓L = ⅘(L − 28)
Multiply both sides by 15:
5L = 12(L − 28)
Distribute:
5L = 12L − 336
Combine like terms:
336 = 7L
Divide:
L = 48
Please help me or assist me in answering this Thank you 5 2/3 X 6 7/8
Answer: 38 23/24
Step-by-step explanation:
Turn the mixed numbers into improper fractions
5 * 3 = 15
15 + 2 = 17
17/3
————————
6 * 8 = 48
48 + 7 = 55
55/8
————————
Now multiply the improper fractions
17/3 * 55/8
17 * 55 = 935
3 * 8 = 24
Divide 935 by 24 to get the answer as a mixed number.
935 / 24 = 38.95833
0.95833/1 = 23/24
935/24 as a mixed number is 38 23/24
Answer: 119 / 4
Step-by-step explanation:
5 2/3 x 6 7/8
= 17/3 x 6 x 7/8
= 17 x 2 x 7/8
= 17 x 2 x 7/8
= 17 x 7/4
= 119 / 4
what is the distance of the ramp in feet? in the picture and please help answer the question below !!!
Answer:
Option 2) Sin 35 = [tex]\frac{5}{x}[/tex]
Step-by-step explanation:
Sin 35 = [tex]\frac{opposite }{hypotenuse}[/tex]
Where opposite = 5' and hypotenuse = x(unknown)
=> Sin 35 = [tex]\frac{5}{x}[/tex]
Check all of the points that are solutions to the system of inequalities.
y> 4x + 2
y< 4x + 5
Someone help me ASAP
Answer:
It is only (5,24).
Step-by-step explanation:
You are correct.
Sometimes, check all options means there could be just one option.
Approximately 8% of all people have blue eyes. Out of a random sample of 20 people, what is the probability that 2 of them have blue eyes? Round answer to 4 decimal places. Answer:
Answer:
27.11% probability that 2 of them have blue eyes
Step-by-step explanation:
For each person, there are only two possible otucomes. Either they have blue eyes, or they do not. The probability of a person having blue eyes is independent of any other person. So we use the binomial probability distribution to solve this question.
Binomial probability distribution
The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.
[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]
In which [tex]C_{n,x}[/tex] is the number of different combinations of x objects from a set of n elements, given by the following formula.
[tex]C_{n,x} = \frac{n!}{x!(n-x)!}[/tex]
And p is the probability of X happening.
8% of all people have blue eyes.
This means that [tex]p = 0.08[/tex]
Random sample of 20 people:
This means that [tex]n = 20[/tex]
What is the probability that 2 of them have blue eyes?
This is P(X = 2).
[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]
[tex]P(X = 2) = C_{20,2}.(0.08)^{2}.(0.92)^{18} = 0.2711[/tex]
27.11% probability that 2 of them have blue eyes
The probability that 2 of them have blue eyes is 27.11%.
Given that,
Approximately 8% of all people have blue eyes.
Out of a random sample of 20 people,
We have to determine,
What is the probability that 2 of them have blue eyes?
According to the question,
People having blue eyes p = 8% = 0.08
Sample of people n = 20
For each person, there are only two possible outcomes. Either they have blue eyes, or they do not.
The probability of a person having blue eyes is independent of any other person.
The probability that 2 of them have blue eyes is determined by using a binomial probability distribution.
[tex]\rm P (X = x) =n_C_x\times p^x \times (1-p)^{n-x}}[/tex]
Therefore,
The probability that 2 of them have blue eyes is,
[tex]\rm P (X = x) =n_C_x\times p^x \times (1-p)^{n-x}}\\\\ \rm P (X = x) = \dfrac{n!}{(n-x)! \times x!} \times p^x \times (1-p)^{n-x}}\\\\[/tex]
Substitute all the values in the formula,
[tex]\rm P (X = 2) = \dfrac{20!}{(20-2)! \times 2!} \times (0.08)^2 \times (1-0.08)^{20-2}}\\\\ P (X = 2) = \dfrac{20!}{(18)! \times 2!} \times (0.0064) \times (0.92)^{18}}\\\\ P (X = 2) = \dfrac{19\times 20}{ 2} \times (0.0064) \times (0.222)\\\\ P(X = 2) = {19\times 10}\times (0.00142)\\\\P(X = 2) = 0.2711\\\\P(X = 2) = 27.11 \ Percent[/tex]
Hence, The required probability that 2 of them have blue eyes is 27.11%.
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Solve the equation x^3 + 2x^2 - 11x -12 = 0
Answer: there are 4 solutions
x = -2
x = -1/2 = -0.500
x =(3-√5)/2= 0.382
x =(3+√5)/2= 2.618
Step-by-step explanation:
To collect data on the signal strengths in a neighborhood, Briana must drive from house to house
and take readings. She has a graduate student, Henry, to assist her. Briana figures it would take her
12 hours to complete the task working alone, and that it would take Henry 18 hours if he completed
the task by himself.
Answer: Working together, they can complete the task in 7 hours and 12 minutes.
Step-by-step explanation:
Ok, Briana needs 12 hours to complete the task.
Then we can find the ratio of work over time as:
1 task/12hours = 1/12 task per hour.
This means that she can complete 1/12 of the task per hour.
Henry needs 18 hours to complete the task, then his ratio is:
1 task/18 hours = 1/18 task per hour.
This means that he can complete 1/18 of the task in one hour.
If they work together, then the ratios can be added:
R = 1/12 + 1/18 = 18/(12*18) + 12/(18*12) = 30/216
we can reduce it to:
R = 15/108 = 5/36
So, working together, in one hour they can complete 5/36 of the task, now we can find the number of hours needed to complete the task as:
(5/36)*x = 1 task
x = 36/5 hours = 7.2 hours
knowing that an hour is 60 minutes, then 0.2 of an hour is 60*0.2 = 12 minutes.
then x = 7 hours and 12 minutes.
What is the value of AC?
Answer:
0.637
Step-by-step explanation:
The average value of a whole sinusoidal waveform over one complete cycle is zero as the two halves cancel each other out
what are the steps (2+2i)(5+3i)??? please help me
I need help for a grade
Answer:
180
Step-by-step explanation:
2(24)-3=45
24-8=√16=4
45*4=180
The measure of angle O is 600°. The polnt (x, y) corresponding to on the unit circle is?
Answer:
[tex](\frac{-1}{2} , \frac{-\sqrt{3} }{2} )[/tex]
Step-by-step explanation:
Memorize your unit circle.
Step 1: Subtract 360 from 600 degrees to find rotation
600° - 360° = 240°
Step 2: Either find coordinates from unit circle or convert to radians
240° = 4π/3
Step 3: Find coordinates
insert a digit to make numbers that are divisible by 24 if it is possible 38_36
Answer:
ge
Step-by-step explanation:
ge
anyone please answer this
Answer:
21
Step-by-step explanation:
1/5 of 30 is 6
10% of 30 is 3
3+6=9
30-9=21
which is 7/10
Answer:
Simon has 7/10 of the cakes left.
eight less than fout times a number is less than 56. what are the possible values of that number
Answer:
x<16
Step-by-step explanation:
number n
eight less than four times a number ... 4 x n - 8
is less than 56 ... < 56
4 x n - 8 < 56
4 x n < 56 + 8
4 x n < 64/4
n < 64 / 4
n < 16
Answer:
Step-by-step explanation:
Let the number be x
Four times the number : 4x
Eight less than four times a number: 4x - 8
4x - 8 < 56
Now add 8 to both sides,
4x < 56+8
4x < 64
Divide both sides by 4,
x < 64/4
x < 16
Possible values of number = Value less than 16
A service station has both self-service and full-service islands. On each island, there is a single regular unleaded pump with two hoses. Let X denote the number of hoses being used on the self-service island at a particular time, and let Y denote the number of hoses on the full-service island in use at that time. The joint pmf of X and Y appears in the accompanying tabulation.
Y
p(x,y), 0 1 2
0 .10 .04 .02
x 1 .08 .20 .06
2 .06 .14 .30
a. What is P(X = 1 and = 1)?
b. Compute P(X land Y 1).
c. Give a word description of the event {X t- 0 and Y 0}, and compute the probability of this event
d. Compute the marginal pmf of X and of Y. Using pX(x), what is P(X 5 1)?
e. Are X and Y independent rv's? Explain.
Answer:
Step-by-step explanation:
Y
p(x,y) 0 1 2
0 0.10 0.04 0.02
x 1 0.08 0.2 0.06
2 0.0 0.14 0.30
a) What is P(X = 1 and = 1)
From the table above we have
P(1,1) = 0.2
b) Compute P(X ≤ 1 and Y ≤ 1).
[tex]=p(0,0)+p(0,1)+p(1,0)+p(1,1)\\\\=0.1+0.04+0.08+0.2\\\\=0.42[/tex]
C)
Let A ={X ≠ 0 and Y ≠ 0}
p{X ≠ 0 , Y ≠ 0}
= p(1,1) + p(1,2) + p(2,1) + p(2,2)
= 0.20 + 0.06 + 0.14 + 0.30
=0.7
d) The possible X values are in the figure 0,1,2
[tex]p_x(0)=p(0,0)+p(0,1)+p(0,2)\\\\=0.1+0.04+0.02\\\\=0.16\\\\p_x(1)=p(1,0)+p(1,1)+p(1,2)\\\\=0.08+0.2+0.06\\\\=0.34\\\\p_x(2)=p(2,0)+p(2,1)+p(2,2)\\\\=0.06+0.14+0.3\\\\=0.5[/tex]
The possible Y values are in the figure 0,1,2
[tex]p_y(0)=p(0,0)+p(1,0)+p(2,0)\\\\=0.1+0.08+0.06\\\\=0.24\\\\p_y(1)=p(0,1)+p(1,1)+p(2,1)\\\\=0.04+0.2+0.14\\\\=0.38\\\\p_y(2)=p(0,2)+p(1,2)+p(2,2)\\\\=0.02+0.06+0.3\\\\=0.38[/tex]
So the probability of x ≤ 1 is
[tex]p(x\leq 1)=p_x(0)+p_x(1)\\\\=0.34+0.16\\\\=0.50[/tex]
e) From the table
[tex]p_x(x=1,y=1)=p(1,1)\\\\=0.2\\\\p_x(1)=0.34\\\\p_y(1)=0.38[/tex]
we multiply both together
0.34 x 0.38
=0.1292
Therefore p(1,1) is not equal px(1), py(1)
Hence x and y are not independent it is not equal
Mary is running a marathon which is a total of 26 miles. She is running at a pace of 7.5 miles per hour and
has already run 8 miles. If she stays at the same pace, how much time in hours does she have left?
Answer:
2.4 hours
Step-by-step explanation:
If Mary is running 26 miles at a pace of 7.5 miles per hour, it will take her 3.47 hours to run the full course.
26/7.5 = 3.466666...
If she has run 8 miles, 1.07 hours have passed.
8/7.5 = 1.06666666...
Subtract the total time from the time that has already passed to find the time left.
3.47 - 1.07 = 2.4
Mary has 2.4 hours left.
How do you determine the vertex from the vertex from of a quadratic equation
Answer:
it it the highest or lowest point of a parabola
In d e f, d f equals 16 and F equal 26. Find Fe to the nearest tenth
Answer:
14.4 units
Step-by-step explanation:
In Trigonometry
[tex]\cos \theta =\frac{Adjacent}{Hypotenuse}\\[/tex]
In Triangle DEF,
[tex]\cos F =\dfrac{EF}{DF}\\\cos 26^\circ =\dfrac{EF}{16}\\EF=16 \times \cos 26^\circ\\=14.4$ units (correct to the nearest tenth).[/tex]
2ft/sec is how many mph?
Answer:
1.36364
Step-by-step explanation:
I calculated the solution on a calculator
So the answer to 1 d.p is 1.4
A diagnostic test has a 95% probability of giving a positive result when given to a person who has a certain disease. It has a 10% probability of giving a (false) positive result when given to a person who doesn’t have the disease. It is estimated that 15% of the population suffers from this disease.
(a) What is the probability that a test result is positive?
(b) A person recieves a positive test result. What is the probability that this person actually has the disease? (probability of a true positive)
(c) A person recieves a positive test result. What is the probability that this person doesn’t actually have the disease? (probability of a false negative)
Answer:
a)0.2275 b)95/105=19/21 c)10/105= 2/21
Step-by-step explanation:
a) The case "The test result is positive" consists in 2 parts.
The 1st one is "The person has the desease (15%=0.15) and the test's result is positive (95%=0.95)
The probability of that is P(desease, positive) = 0.15*0.95=0.1425
The 2nd one is "The person has no the desease (100%-15%=85%=0.85). However the test result is positive (10%=0.1)
The probability of that is P(not desease, positive)=0.85*0.1=0.085
The total probability that test is positive is the sum of 1st and 2-nd parts of the case: P(pos) = 0.1425+0.085=0.2275
b) As it has been shown in a) The test result can be positive in case that the person is really has the desease (95%) and in case the person has no the desease (10%). This actually means that 95 persons from 105 having positive test result are really has the desease.
So the probability that the test result is positive and person has the desease is P (desease/positive)= 95/105
c) It's clearly seen that the sum of probabilities of b) and c) equal 1.
Both events make full group of events.
If the test result is positive the person can have the desease or can have not the desease. So ( no desease/positive)= 1-95/105=10/105
Please answer this correctly
Answer:
63 points
Step-by-step explanation:
63 points is the lowest score having 6 as "leaf" and 3 as "stem"
Answer:
63 points
Step-by-step explanation:
The lowest score is 63 with a stem of 6 and leaf of 3.
The top figure in the composite figure is called a . And What is the volume?
Answer:
Triangular Prism
volume 748
Consider the graph of the line of best fit, y = 0.5x + 1, and the given data points. A graph shows the horizontal axis numbered negative 4 to positive 4 and the vertical axis numbered negative 4 to positive 4. Points show an upward trend. Which is the residual value when x = 2? –2 –1 1 2
Answer
its -1
Step-by-step explanation:
ED 2020 boiiiii
The residual value of the line of the best fit when x = 2 is -1
How to determine the residual value?The equation of the line is given as:
y = 0.5x + 1
When x = 2, we have:
y = 0.5 * 2 + 1
Evaluate
y = 2
The residual is the difference between the actual value and the predicted value.
From the complete graph, the actual value is 1.
So, we have:
Residual = 1 - 2
Evaluate
Residual = -1
Hence, the residual value when x = 2 is -1
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In the fall semester of 2009, the average Graduate Management Admission Test (GMAT) of the students at a certain university was 500 with a standard deviation of 90. In the fall of 2010, the average GMAT was 570 with a standard deviation of 85.5. Which year's GMAT scores show a more dispersed distribution
Answer:
Due to the higher coefficient of variation, 2009's GMAT scores show a more dispersed distribution
Step-by-step explanation:
To verify how dispersed a distribution is, we find it's coefficient of variation.
Coefficient of variation:
Mean of [tex]\mu[/tex], standard deviation of [tex]\sigma[/tex]. The coefficient is:
[tex]CV = \frac{\sigma}{\mu}[/tex]
Which year's GMAT scores show a more dispersed distribution
Whichever year has the highest coefficient.
2009:
Mean of 500, standard deviation of 90. So
[tex]CV = \frac{90}{500} = 0.18[/tex]
2010:
Mean of 570, standard deviation of 85.5. So
[tex]CV = \frac{85.5}{570} = 0.15[/tex]
Due to the higher coefficient of variation, 2009's GMAT scores show a more dispersed distribution
2009's GMAT scores show a more dispersed distribution.
Given that in 2009: Mean = 500 and standard deviation = 90.
In 2010: Mean = 570 and standard deviation = 85.5.
If the standard deviation is higher then the scores will be more dispersed.
Note that: 90 > 85.5. And 90 corresponds to 2009.
So, 2009's GMAT scores show a more dispersed distribution.
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Simplify 18 - 2[x + (x - 5)]. 28 - 4 x 8 - 4 x 28 - 2 x
Answer:
[tex]-4x+28[/tex]
Step-by-step explanation:
[tex]18-2(x+x-5)[/tex]
[tex]18+(-2)(x)+(-2)(x)+(-2)(-5)[/tex]
[tex]18+-2x+-2x+10[/tex]
[tex]-2x-2x+10+18[/tex]
[tex]=-4x+28[/tex]
HELP HELP HELP PLEASE!!!!!
A party rental company has chairs and tables for rent. The total cost to rent 2 chairs and 3 tables is $31. The total cost to rent 6 chairs and 5 tables is $59
What is the cost to rent each chair and each table?
Answer:
The rental of each chair is $2.75
The rental of each table is $8.5
Step-by-step explanation:
Let's name the unknowns "c" for the cost of each chair rental, and "t" for the cost of each table rental.
Now we can create the equations that represent the statements:
a) "The total cost to rent 2 chairs and 3 tables is $31."
2 c + 3 t = 31
b) "The total cost to rent 6 chairs and 5 tables is $59."
6 c + 5 t = 59
now we have a system of two equations and two unknowns that we proceed to solve via the elimination method by multiplying the first equation we got by "-3" so by adding it term by term to the second equation, we eliminate the variable "c" and solve for "t":
(-3) 2 c + (-3) 3 t = (-3) 31
-6 c - 9 t = -93
6 c + 5 t = 59
both these equations added give:
0 - 4 t = -34
t = 34/4 = 8.5
So each table rental is $8.5
now we find the rental price of a chair by using any of the equations:
2 c + 3 t = 31
2 c + 3 (8.5) = 31
2 c + 25.5 = 31
2 c = 5.5
c = 5.5/2
c = $2.75
Two similar circles are shown. The circumference of the larger circle, with radius OB, is 3 times the circumference of the smaller circle, with radius OA. Two circles are shown. The smaller circle has radius O A and the larger circle has radius O B. Radius OB measures x units. Which expression represents the circumference of the smaller circle with radius OA? (StartFraction pi Over 3 EndFraction)x units (StartFraction 2 pi Over 3 EndFraction)x units 2πx units 6πx units
Answer:
its 2pi/3
Step-by-step explanation:
because the full radian measure of a circle is 2pi radians, the smaller circle is a third of the size of the larger one. Multiply straight across for (2pi/1)(1/3)
The circumference of the smaller circle can be given by [tex]\dfrac{2\times \pi}{m}(x)\ units[/tex].
Given to us,Two similar circles are shown.The circumference of the larger circle, with radius OB, is 3 times the circumference of the smaller circle, with radius OA. The smaller circle has radius O A and the larger circle has radius O B. Radius OB measures x units. Circumference of the larger circle[tex]\rm{Circumference\ of\ the\ circle = 2\times \pi \times (radius)[/tex]
[tex]\rm{Circumference\ of\ the\ circle = 2\times \pi \times (OB)[/tex]
[tex]\rm{Circumference\ of\ the\ circle = 2\times \pi \times (x)[/tex]
Circumference of the smaller circle,Circumference of the Larger circle = 3 x Circumference of the smaller circle
[tex]2\times \pi \times x = 3\times Circumference\ of\ the\ smaller\ circle\\\\3\times Circumference\ of\ the\ smaller\ circle = 2\times \pi \times x \\\\Circumference\ of\ the\ smaller\ circle = \dfrac{2\times \pi \times x }{3}\\\\Circumference\ of\ the\ smaller\ circle = \dfrac{2\times \pi}{3}( x )\ units[/tex]
Hence, the circumference of the smaller circle can be given by [tex]\dfrac{2\times \pi}{m}(x)\ units[/tex].
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