State the null hypothesis, Ho, and the alternative hypothesis, Ha, that would be used to test these claims.

Question

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(a) There is an increase in the mean difference between posttest and pretest scores.
Ho: ¦Ìd 0
Ha: ¦Ìd 0

(b) Following a special training session, it is believed that the mean of the difference in performance scores will not be zero.
Ho: ¦Ìd 0
Ha: ¦Ìd 0

(c) On average, there is no difference between the readings from two inspectors on each of the selected parts.
Ho: ¦Ìd 0
Ha: ¦Ìd 0

(d) The mean of the differences between pre-self-esteem and post-self-esteem scores showed improvement after involvement in a college learning community.
Ho: ¦Ìd 0
Ha: ¦Ìd 0