Question

Please state the null and alternative hypothesis for both examples.

An education researcher wants to learn whether it is more effective to put questions before or after introducing a new concept in an elementary school mathematics text. He prepares two text segments that teach the concept, one with motivating questions before and the other with review questions after. He uses each text segment to teach a separate group of children. The researcher compares the scores of the groups on a test over the material.

Does stress affect the recall ability of police eyewitnesses? This issue was studied in an experiment that tested eyewitness memory a week after a non-stressful interrogation of a cooperative suspect and a stressful interrogation of an uncooperative and belligerent suspect. The number of details recalled a week after the incident was recorded.

Answer 1

In example 1 two separate means are compared:

Null hypothesis: there is no significant difference among the means

Alternate hypothesis: there is a significant difference among the means

In the second example

Null hypothesis: the mean of difference in memory is zero ( non significant )

Alternate hypothesis:   the mean of difference in memory is significant