Let ? denote the true average tread life of a certain type of tire. Consider testing H0: ? = 30,000 versus Ha: ? > 30,000 based on a sample of size n = 16 from a normal population distribution with ? = 1500. A test with ? = 0.01 requires z? = z0.01 = 2.33. The probability of making a type II error when ? = 31,000 is ?        = Φ   2.33 +  30,000 − 31,000 1500/   16     = Φ         (rounded to two decimal places)   = 0.3669

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

Let ? denote the true average tread life of a certain type of tire. Consider testing H0: ? = 30,000 versus Ha: ? > 30,000 based on a sample of size n = 16 from a normal population distribution with ? = 1500. A test with ? = 0.01 requires z? = z0.01 = 2.33. The probability of making a type II error when ? = 31,000 is

?
 
  
 
= Φ
 
2.33 + 
30,000 − 31,000
1500/
  16
 
 
= Φ
 
  
 
 (rounded to two decimal places)
 
= 0.3669

Since z0.1 = 1.28, the requirement that the level 0.01 test also have ?(31,000) = 0.1 necessitates

n = 
 
1500(2.33 + 1.28)
30,000 − 31,000
  2
 
 = (−5.42)2 = 
 (rounded to two decimal places).

The sample size must be an integer, so n =  (rounded up to the next whole number) tires should be used.

Expert Solution
steps

Step by step

Solved in 5 steps

Blurred answer
Similar questions
  • SEE MORE QUESTIONS
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