business statistics
posted by Laritza .
Please, only formula and steps to do these exercises. Thank you
For the following data from independent samples, could the null hypothesis that the population means are equal be rejected at the 0.05 level?
Sample1 Sample2 Sample3 Sample4
15.2 10.2 14.9 11.5
12.2 12.1 13.0 13.1
15.0 8.5 10.8 11.5
14.6 8.1 10.7 6.3
9.7 10.9 13.3 12.0
13.6 10.6 8.7
8.5 11.9
Safety researchers, interested in determining whether the occupancy of a vehicle might be related to the speed at which the vehicle is driven, have observed the following speed (mph) measurements for two random samples of vehicles.
Driver alone 64 50 71 55 67 61 80 56 59 74 at least one
Passenger 44 52 54 48 69 67 54 57 58 51 62 67
a. What are the null and alternative hypotheses for this test?
b. Use ANOVA and the 0.025 level of significance in testing the null hypothesis identified in part (a).
c. For each sample, construct the 95% confidence interval for the population mean.
Alone WithPass
64 44
50 52
71 54
55 48
67 69
61 67
80 54
56 57
59 58
74 51
62
67
Three racqueball players, one from each skill level, have been randomly selected from the membership list of a health club. Using the same ball, each person hits five serves, one with each of five racquets, and using the racquets in a random order. Each serve is clocked with a radar gun, and the results are shown here. With player skill level as a blocking variable, use the 0.025 level of significance in determining whether the treatment effects of the five racquets could all be zero. Using the 0.01 level, evaluate the effectiveness of the blocking variable. Player Skill Level
Beginner Intermed Advance
RacqtA 73 64 83
RacqtB 63 72 89
RacqtC 51 54 72
RacqtD 56 81 86
RacqtE 69 90 97
Given the following data for a twoway ANOVA, identify the sets of null and alternative hypotheses, then use the 0.05 level in testing each null hypothesis.
B1 B2 B3
A1 152 158 160
151 154 160
A2 158 164 152
154 158 155
A3 160 147 147
161 150 146

http://www.justanswer.com/uploads/Sk1llz/20081218_234257_11.doc

Z = (mean1  mean2)/ Sq rt (SD1^2 + SD2^2)
Seek smallest value in table labeled something like "areas under normal distribution."
I hope this helps a little more. Thanks for asking.