Suppose you use Google Analytics to optimize your online adds. You run two different ads, ad A and ad B, for a month. What is a appropriate test statistics for the click rate and appropriate critical p value?

Select one:

a.

Use the difference in the click rates of ad A and ad B and chose the ad with the higher click rate for future campaigns.

b.

Compute a t-statistics as the difference in the click ratesdivided by the standard error of the difference. Select an appropriate level for the critical p value and reject if the p-value associated with the computed t-value is smaller than the critical p-value. Use your domain knowledge to explain what you found.

c.

Compute the difference in the click rates and find the appropriate p value. If it is larger than 0.05 then reject the null hypothesis that there is no difference and use the add with the higher click rate.

d.

Compute the t-statistics as the ratio of the click rates. Use statistical hypothesis testing with p=0.05 to decide if the t-statistics is statistically significant different from 1.