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Question 1
Marks: 1
We have discussed that the standard deviation of the distribution of sample percentages
or SE(p hat) is calculated by taking the square root of
p hat * (1  p hat)/ N , where p hat is the proportion in the sample and N is sample size
What does SE(p hat) show?
Choose one answer.
A. It shows the distribution of p hat for the single sample that the researcher draws
from the population.
B. It shows the standard deviation of the p hat distribution.
C. It shows the standard deviation of the P distribution.
D. It shows the standard deviation of the Xbar distribution.
Correct
Marks for this submission: 1/1.
Question 2
Marks: 1
Suppose that you want to estimate the 99% CI for the average number of hours that
middle school students play video games per month. For a random sample of 100 middle
school students, the mean and standard deviation for the number of hours that they play
video game per month is 7 and 2 respectivley.
What is the best answer?
Choose one answer.
A. We are 99% confident that the mean number of hours that students in this sample
play video grams per month is between 6.5 to 7.5 hours.
B. We are 99% confident that the mean number of hours that middle school students
play video grams per month is between 6.5 to 7.5 hours.
C. We are 99% confident that 95 out of 100 middle school students play between
6.5 to 7.5 hours of video game per month.
D. We are 99% confident that if we took one hundred random samples in 95 of them
the mean number of hours for playing video game per month would be between 6.5
to 7.5 hours.
Correct
Marks for this submission: 1/1.
Question 3
Marks: 1
Reseaerchers A, B, abd C have each selected a random sample of 300 freshmen from
universities A, B, and C and computed the 95% CI for SATQ (SAT quantitative). The
universities they sampled from all have around 30,000 students.
Researcher A finds the CI to be from 490 to 510.
Researcher B finds the CI to be from 610 to 630.
Researcher C find the CI to be from 450 to 470.
Given that the average of the SATQ in the population is 500, what is the best answer?
Choose one answer.
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View Full Document A. Universities A, B, and C are average, more competitive, and less competitive
respectively.
B. Universities A, B, and C are less competitive, more competitive, and average
respectively.
C. Universities A, B, and C are more competitive, less competitive, and average
respectively.
D. Unversities A,B, and C are less competitive, average, and more competitive
respectively.
Correct
Marks for this submission: 1/1.
Question 4
Marks: 1
An undergraduate student has been hired to work on a research project. One of the
objectives of this project is to find out if the age at which college graduates get married
(first marriage) is higher than 27. She reports the following data for a random sample of
225 college graduates.
95% confidence interval for the age at the time of marriage: (22, 28)
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This note was uploaded on 05/02/2011 for the course STAT 101A taught by Professor Mahtashesfandiari during the Winter '11 term at UCLA.
 Winter '11
 MahtashEsfandiari
 Standard Deviation, The Federalist Papers

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