Homework: Chapter 9 Required Practice Score: 0.2 of 1 pt 16 of 17 (17 complete)
ID: 2945817 • Letter: H
Question
Homework: Chapter 9 Required Practice Score: 0.2 of 1 pt 16 of 17 (17 complete) 9.2.43 People wore polled on how many books they read the previous year. Initial survey results indicate that s- 17.9 books. Compiete parts (a) through (d) below Click the icon to view a partial table of critical values. inisy5% confidence level requires 35 subjects. (Round up to the nearest subject (b) How many subjects are needed to estmatethe mean rum ber of books read the previous year within three books with 95% confidence? This 95% confidence level requires 137 subjects. (Round up to te nearest subject ) (c) What effect does doubling the required accuracy have on the sample size? A. Doubling the required accuracy nearly quadruples the sample size. B Doubling the required accuracy nearly doubles the sample size c Doting the required accuracy nearly halves the sample size D. Doubling the required accuracy nearly quarters the sample size (d) How many subjects are needed to estimate the mean number of books read the previous year within six books This 00% oor-fidence level require«Dsub ects. (Round up to the nearest subject.) Enter your answer in the answer box and then click Check Answer with 99% confidence?Explanation / Answer
Answer to part d
we have margin of error = 6 books
standard deviation = 17.9 books
z score for 99% confidence interval is 2.576
using the formula
sample size = [(z*s)/ME]^2
n(sample size) = [(2.576*17.9)/6]^2 = (46.1104/6)^2 = (7.6851)^2 = 59.06
so, the required sample size is 59(rounded to nearest subject)
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