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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 (蟽)=50

Confidence Interval=95%

E=2

02

Concept Used

Formula to be used is:

n=z伪2脳蟽E2

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

03

Calculation

Hence, n=32脳蟽E2

=1.96脳5022

=2401

Sample size is2401

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Most popular questions from this chapter

Suppose we want a 90% confidence interval for the average amount spent on books by freshmen in their first year at a major university. The interval is to have a margin of error of at most \(2. Based on last year鈥檚 book sales, we estimate that the standard deviation of the amount spent will be close to \)30. The number of observations required is closest to which of the following?

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