A random sample of 15 graduates of a certain secretarial school typed an average of 76.7 words per minute with a standard deviation of 7.8 words per minute. Assuming a normal distribution for the number of words typed per minute, find a 90% 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...
icon
Related questions
Question

solve the following

A random sample of 15 graduates of a certain secretarial school typed an average of 76.7 words per minute with a standard deviation of 7.8 words per minute. Assuming a normal distribution for the number of words typed per
minute, find a 90% 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 <<
(Round to two decimal places as needed.)
C
Transcribed Image Text:A random sample of 15 graduates of a certain secretarial school typed an average of 76.7 words per minute with a standard deviation of 7.8 words per minute. Assuming a normal distribution for the number of words typed per minute, find a 90% 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 << (Round to two decimal places as needed.) C
Expert Solution
steps

Step by step

Solved in 3 steps with 1 images

Blurred answer
Recommended textbooks for you
A First Course in Probability (10th Edition)
A First Course in Probability (10th Edition)
Probability
ISBN:
9780134753119
Author:
Sheldon Ross
Publisher:
PEARSON
A First Course in Probability
A First Course in Probability
Probability
ISBN:
9780321794772
Author:
Sheldon Ross
Publisher:
PEARSON