SOLUTION: While writing an article on the high cost of college education, a reporter took a random sample of the cost of new textbooks for a semester. The random variable x is the cost of on
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Question 856515: While writing an article on the high cost of college education, a reporter took a random sample of the cost of new textbooks for a semester. The random variable x is the cost of one book. Her sample data can be summarized by the following. (Give your answers correct to two decimal places.)
n = 27, Σx = 3689.6, and Σ(x - x)2 = 9809.4
(a) Find the sample mean, x.
$
(b) Find the sample standard deviation, s.
$
(c) Find the 90% confidence interval to estimate the true mean textbook cost for the semester based on this sample.
Hi,
use 136.65 for mean and 6.15 for ME
n = 27, Σx = 3689.6, and Σ(x - x)2 = 9809.4
mean = 3689.6/27 = 136.65
SD = = 19.42
ME = 1.645(19.42)/sqrt(27) = 6.15
136.65 - 6.15 < < 136.65 + 6.15
130.5 < < 142.8
