Question

A researcher is looking into whether who wear Crocs sandals are less cool than people who wear other sandals. He knows that the mean “coolness” score for people who wear other sandals is 21, with a population standard deviation of 6. He takes a sample of 9 people who wear Crocs and finds a sample mean coolness score of 17.4. What is the probability of finding this result or lower, if the null hypothesis is true?

a. .6844

b. .9912

c. .0792

d. .0359

Answer 1

Solution :

= 21

=17.4

=6

n = 9

This is the left tailed test .

The null and alternative hypothesis is ,

H0 :    = 21

Ha : < 21

Test statistic = z

= ( - ) / / n

= (17.4-21) / 6 / 9

= -1.8

Test statistic = z = -1.8

P(z < -1.8 ) = 0.0359

P-value = 0.0359

Option d ) is correct.