10.1_review_a___c (2).doc - Name: 10.1A and C Review AP...

Name: AP Statistics
10.1A and C Review
Suppose you administer a certain aptitude test to a random sample of 9 students in your school, and that the
average score is 105. We want to determine the mean µ of the population of all students in the school. Assume
a standard deviation of  = 15 for the test.
1. What is the upper critical value for a 98% confidence interval? (Show the key numbers in the sketch of the
distribution.)
-3.0 3.0
.50
-.50
2. Explain the meaning of “98% confident.”
3. What is the standard deviation of the mean,
x

4. Calculate a 98% confidence interval for the mean score µ for the whole school. Follow the Inference
Toolbox.
5. What sample size would be needed to have a margin of error at most 4 points?
?
Chapter 10

From a population with standard deviation 25, a sample of size 100 is drawn. The mean of the sample is 235.
1. Find z * for a 90% confidence interval for the true mean of the