Question

In a study of cell phone use an internet survey was randomly emailed to 5000 subjects. From the surveys emailed out, 717 were returned. Use a 0.01 significance level to test the claim that the return rate is less than 15%.0__________________________________________AHH

Determine the Test Criteria: z = ____________________________

Calculate out the Test Statistic: z = __________________________

Decision: ______________________________________________

Answer 1

Solution:

Null and alternative hypothesis are

H0 : p = 0.15

H1 : p < 0.15

Determine the Test Criteria:

= 0.01

< sign in H1 , so LEFT TAILED TEST

Critical value is =   = -2.33

Decision criteria: Reject H₀ if z < -2.33

Calculate out the Test Statistic:

Let   be the sample proportion.

= x/n = 717/5000 = 0.1434

z =   

=  (0.1434 - 0.15)/[0.15*(1 - 0.15)/5000]

= -1.31

Test Statistic z = -1.31

Decision: Do not reject H₀

(because -1.31 is not less than -2.33 )