Help Please.

A researcher asks whether attending a private high school leads to higher or lower performance on a test of social skills when compared to students attending public schools. A sample of 100 students from a private school produces a mean score of 71.30. The population mean (m) for students from public high schools is 75.62. The population standard deviation is 28. Zobt is –1.54. Zcrit is ± 1.96.
Question:

•Should the researcher use a one-tailed or a two-tailed test? Why?

Question

Help Please.

A researcher asks whether attending a private high school leads to higher or lower performance on a test of social skills when compared to students attending public schools. A sample of 100 students from a private school produces a mean score of 71.30. The population mean (m) for students from public high schools is 75.62. The population standard deviation is 28. Zobt is –1.54. Zcrit is ± 1.96.
Question: 

•Should the researcher use a one-tailed or a two-tailed test? Why?

dumbcow · Answer

one-tailed test, you want to know if private school scores are significantly lower than public school scores

Null Hypothesis: X = 75.62
Alternative Hypothesis: X < 75.62