SOLUTION: The proportion of cell phone users with 4G contracts last year was p=.62. A Verizon excutive thinks this has increased this year. A random sample of 350 users found 238 users have

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Question 1139306: The proportion of cell phone users with 4G contracts last year was p=.62. A Verizon excutive thinks this has increased this year. A random sample of 350 users found 238 users have 4G contracts.
(a) Idenitify the Null and Alternative Hypotheses.
(b) Assuming you want a significant level of 0.05, determine the critical value of the hypoth- esis test.
(c) Calculate the test statistic for the test.
(d) Do you reject or fail to reject the null hypothesis?

Answer by adamsmith9037(4) About Me  (Show Source):
You can put this solution on YOUR website!
a. null hypothesis (H0): p = 0.62
alternative hypothesis (H1): p>0.62
b. x ~ B(350,0.62)
let the critical value be k.
P(X≥k)<0.05
1-P(X≤k-1)<0.05
P(X≤k-1)<0.95
from the binomial cumulative calculator,
k-1=232
hence, k=233
c. critical region 233≤X≤350
acceptance region 0≤X≤232
d. since 238 lies in the critical region, the null hypothesis is REJECTED and there has been indeed an increase of cell phone users with 4G contract.