A random sample of 12 graduates of a certain secretarial school typed an average of 81.3 words per minute with a standard deviation of 7.3 words per minute. Assuming a normal distribution for the number of words typed per minute, find a 95% confidence interval for the average number of words typed by all graduates of this school. Click here to view page 1 of the standard normal distribution table. Click here to view page 2 of the standard normal distribution table. Click here to view page 1 of the table of critical values of the t-distribution. Click here to view page 2 of the table of critical values of the t-distribution. The confidence interval is ]<µ< [ (Round to two decimal places as needed.)

A First Course in Probability (10th Edition)
10th Edition
ISBN:9780134753119
Author:Sheldon Ross
Publisher:Sheldon Ross
Chapter1: Combinatorial Analysis
Section: Chapter Questions
Problem 1.1P: a. How many different 7-place license plates are possible if the first 2 places are for letters and...
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A random sample of 12 graduates of a certain secretarial school typed an average of 81.3 words per minute with a standard
deviation of 7.3 words per minute. Assuming a normal distribution for the number of words typed per minute, find a 95%
confidence interval for the average number of words typed by all graduates of this school.
Click here to view page 1 of the standard normal distribution table.
Click here to view page 2 of the standard normal distribution table.
Click here to view page 1 of the table of critical values of the t-distribution.
Click here to view page 2 of the table of critical values of the t-distribution.
The confidence interval is
<p<
(Round to two decimal places as needed.)
Transcribed Image Text:A random sample of 12 graduates of a certain secretarial school typed an average of 81.3 words per minute with a standard deviation of 7.3 words per minute. Assuming a normal distribution for the number of words typed per minute, find a 95% confidence interval for the average number of words typed by all graduates of this school. Click here to view page 1 of the standard normal distribution table. Click here to view page 2 of the standard normal distribution table. Click here to view page 1 of the table of critical values of the t-distribution. Click here to view page 2 of the table of critical values of the t-distribution. The confidence interval is <p< (Round to two decimal places as needed.)
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