a researcher computes a one-sample z test in two studies. both studies used the alpha level, placed the rejection region in both tails, and measured the sample mean. The researcher selects a sample of 30 participants in study 1 and decides to retain the null hypothesis. She selects a sample of 60 participants in study 2 and decides to reject the null hypothesis. Which of the following is the best explanation for why thedecision was different in study 1 and study 2?
the different decisions in both study 1 & study 2 are not possible because all values were the same
the different decisions in both study 1 & study 2 are not possible because the researcher tested the same hypothesis
the different decisions in both study 1 & study 2 are due to an error the researcher made in the 1st hypothesis test
the different decisions in both study 1 & study 2 are possible because the second test was associated with a greater power to detect an effect