Question

1. A sociologist thinks that middle school boys spent less time studying in 1981 than middle school boys do today. A study was conducted in 1981 to find the time that middle school boys spent studying on weekdays. The results (in minutes per weekday) are shown below.

31.9	32.1	39.1	36.6	24.2
38.8	21.9	36.2	26.9	35.5
33.8	28.0	35.4	31.9	29.6
27.7	37.1	36.8	36.9	28.5
35.4	28.7	30.5	34.3	34.2
35.9	30.0	32.6	33.0	35.7
28.7	33.8	30.2	41.1	25.3

Recently a similar study was conducted. The results are shown below.

44.7	55.0	49.4	51.3	45.4
47.2	41.1	42.2	54.8	50.0
47.1	51.0	43.0	42.9	49.8
51.5	52.8	49.6	39.0	48.6
54.6	44.7	47.2	40.2	47.9
58.0	46.7	52.0	48.7	54.4
45.5	41.1	46.6	45.6	50.0

At α = 0.05, do middle school boys study more today than in 1981? You can assume that the population approaches a normal distribution.

Answer 1

From the given data

(1) Null and Alternative Hypothesis:

H0: Middle school boys study is not more today than in 1981

H1: Middle school boys study is more today than in 1981

i.e.

Thus we conclude that middle school boys study is more today than in 1981