A researcher drew the sample of 400 people, measured their IQ's, and tested null hypothesis that Uiq = 100. The researcher obtained z = +3.00, which led her to reject hypothesis (o was 15.0). (A) what was the standard error of the mean? (B) what was the mean of the sample? (C) the test yielded a statistically significant outcome. does it appear to be an important one? Explain. (D) how much of a standard deviation did the discrepancy between X and Uhyp amount to?