1. Does listening to music affect how many words you can memorize? Student researchers tried to answer this question by having 20 subjects listen to music while trying to memorize words and also had the same 20 subjects try to memorize words when not listening to music. They randomly determined which condition was done first for each of their subjects. Here are their hypotheses: Null: The average of the difference in number of words memorized (no music ? with music) is 0 (?_d= 0). Alternative: The average of the difference in number of words memorized (no music ? with music) is greater than 0 (?_d> 0). The students found the following results in terms of number of words memorized:

	No music	With music	Difference
Mean	1212	9.99.9	2.12.1
Standard deviation	3.553.55	3.083.08	3.473.47

Q. The standard deviation of the null distribution is 0.974. Use this to find the standardized statistic for this test.Round your answer to 3 decimal places, e.g. 5.836.

=

2. Is a basketball player's ability to make free throws different when they get their own rebound or when someone else gets their rebound for them? This is what student researchers wanted to explore. The researchers used students (20 females and 20 males) taking a college physical education class as their subjects. The students each attempted 10 shots from the free throw line where they had to get their own rebound and 10 shots where someone else got their rebound and passed the ball back to them while they stayed on the free throw line. They randomly determined the order that they took these shots, with some getting their own rebounds first and some having someone else get the rebounds first. Here are the hypotheses.

H₀: There is no association between how the ball is rebounded and the number of shots made(?d=0).(?d=0).

H_a: There is an association between how the ball is rebounded and the number of shots made(?d?0).(?d?0).

The students found the following results for the number of baskets made.

	Rebounded	Self-rebounded	Difference
Mean	3.875	3.000	0.875
Standard deviation	2.399	2.320	1.977

Assuming a true null hypothesis, we simulated this study and found 5,000 mean differences that are shown in the null distribution below.

Mean = 0.000 SD = 0.336 - 1.20 0.90 -0.60 -0.30 0.00 0.30 0.60 0.90 1.20 Average difference