A researcher is interested in whether high school students who play sports have a higher or lower body mass index (BMI) than students in the general population. The researcher is unsure whether playing sports will decrease body mass (due to more calories burned) or increase body mass (due to more muscle mass). He compares their average BMI to that of students in the general population and finds that z_obt = +1.92. This is a _____ test and the researcher should conclude _____. A)one-tailed; that students who are athletes have significantly higher BMIs. B)two-tailed; that students who are athletes have significantly higher BMIs. C)one-tailed: that students who are athletes do not have significantly higher BMIs. D)two-tailed: that students who are athletes do not have significantly higher BMIs.

Question

Quizplus · Accepted Answer

The test is two-tailed because the researcher is unsure of the direction of the effect. A z-value of +1.92 does not reach the typical significance level of 1.96 for a two-tailed test at the 0.05 level, so the conclusion is that there is no significant difference.

A Researcher Is Interested in Whether High School Students Who