Answer:
a) The null and alternative hypothesis are:
b) Test statistic z = -1.3258
c) P-value = 0.1849
Step-by-step explanation:
a) As the reseracher want to determine if the proportion of their users who use Firefox is significantly different from 0.2, it is a two-tailed test, as a proportion significantly low or significantly high gives evidence to support the alternative hypothesis.
Then the null and alternative hypothesis are:
b) The sample has a size n=200.
The sample proportion is p=0.16.
The standard error of the proportion is:
Then, we can calculate the z-statistic as:
c) This test is a two-tailed test, so the P-value for this test is calculated as:
As the P-value (0.1849) is greater than the significance level (0.05), the effect is not significant.
The null hypothesis failed to be rejected.
There is not enough evidence to support the claim that the proportion of their users who use Firefox is significantly different from 0.2