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Chapter 8: Q 78. (page 543)

The SAT againHigh school students who take the SAT Math exam a second time

generally score higher than on their first try. Past data suggest that the score increase has a standard deviation of about 50points. How large a sample of high school students would be needed to estimate the mean change in SAT score to within 2 points with 95%confidence?

Short Answer

Expert verified

Sample size is 2401.

Step by step solution

01

Given Information

It is given that (σ)=50

Confidence Interval=95%

E=2

02

Concept Used

Formula to be used is:

n=zα2×σE2

Using table, value of Za2=1.96corresponding to 95%confidence interval.

03

Calculation

Hence, n=32×σE2

=1.96×5022

=2401

Sample size is2401

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Most popular questions from this chapter

A plethora of pepperoni? Refer to Exercise 73.

a. Explain why it was necessary to inspect a graph of the sample data when checking the Normal/Large Sample condition.

b. According to the manager of the restaurant, there should be an average of 40

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e. If the procedure were repeated many times, 95%of the time the sample mean systolic blood pressure would be between 122and138.
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