A Study Was Conducted to Investigate the Effect of Coaching

Multiple Choice

A study was conducted to investigate the effect of coaching on IQ tests. Nine randomly selected students were tested. Set up the null hypothesis for the claim that the coaching is effective in increasing scores.

A) H₀: The probability distribution of test scores before and after the coaching is identical.
B) H₀: The probability distribution of test scores before the coaching is shifted to the left of the probability distribution of the test scores after the coaching.
C) H₀: The probability distribution of test scores before the coaching is shifted to the right of the probability distribution of the test scores after the coaching.
D) H₀: The probability distribution of test scores before the coaching is shifted to the left or right of the probability distribution of the test scores after the coaching.