statistics

statistics

1. If an experiment is conducted with 5 conditions and 6 subjects in each condition, what are dfn and dfe?

2. The following data are from a hypothetical study on the effects of age and time on scores on a test of reading comprehension. Compute the analysis of variance summary table.
12 year olds 16 year olds
30 minutes 66
68
59
72
46 74
71
67
82
76
60 minutes 69
61
69
73
61 95
92
95
98
94

3. (AT) The dataset ADHD Treatment has four scores per subject. a. Is the design between-subjects or within-subjects? b. Create an ANOVA summary table. http://onlinestatbook.com/2/case_studies/adhd.html

4. (AT) Using the Anger Expression Index from the Angry Moods study as the dependent variable, perform a 2×2 ANOVA with gender and sports participation as the two factors. Do athletes and non-athletes differ significantly in how much anger they express? Do the genders differ significantly in Anger Expression Index? Is the effect of sports participation significantly different for the two genders? http://onlinestatbook.com/2/case_studies/adhd.html

Use for 5&6 :Data are randomly collected from five teenagers in each region of the country. The numbers represent the age at which teenagers obtained their drivers licenses.
H0:µ1 =µ2 =µ3 =µ4 =µ5 Hα: At least any two of the group means µ1,µ2, …,µ5 are not equal.
Northwest south West central east
16.3 16.9 16.4 16.2 17.1
16.1 16.5 16.5 16.6 17.2
16.4 16.4 16.6 16.5 16.6
16.5 16.2 16.1 16.4 16.8
x-=
s2
5. Degrees of freedom – numerator: df(num) = _________

6. Fstatistic = ________
7. A researcher wants to know if the mean times (in minutes) that people watch their favorite news station are the same. Assume that all distributions are normal, the four population standard deviations are approximately the same, and the data were collected independently and randomly. Use a level of significance of 0.05.

Cnn Fox local
45 15 72
12 43 37
18 68 56
38 50 60
23 31 51
35 22

a. H0: _______
b. Ha: _______
c. In words,CLEARLYstate what your random variable X ¯ or P′ represents.
d. State the distribution to use for the test. e. What is the test statistic?
f. What is thep-value? In one or two complete sentences, explain what the p-value means for this problem.
g. Indicatethecorrectdecision(“reject”or“donotreject”thenullhypothesis),thereasonforit,andwriteanappropriate conclusion, usingcomplete sentences.
i. Alpha: _______
ii. Decision: _______
iii. Reason for decision: _______
iv. Conclusion: _______
i. Construct a 95% confidence interval for the true mean or proportion.
8. Are the mean number of times a month a person eats out the same for whites, blacks, Hispanics and Asians? Assume that all distributions are normal, the four population standard deviations are approximately the same, and the data were collected independently and randomly. Use a level of significance of 0.05.
White Black Hispanic asian
6 4 7 8
8 1 3 3
2 5 5 5
4 2 4 1
6 6 7

a. H0: _______
b. Ha: _______
c. In words, CLEARLY state what your random variable X ¯ or P′ represents.
d. State the distribution to use for the test. e. What is the test statistic?
f. What is thep-value? In one or two complete sentences, explain what the p-value means for this problem.
g. Indicate the correct decision (“reject” or “do not reject” the null hypothesis), the reason for it, and write an appropriate conclusion, using complete sentences.
i. Alpha: _______
ii. Decision: _______
iii. Reason for decision: _______
iv. Conclusion: _______
i. Construct a 95% confidence interval for the true mean or proportion.
9. A grassroots group opposed to a proposed increase in the gas tax claimed that the increase would hurt working-class people the most, since they commute the farthest to work. Suppose that the group randomly surveyed 24 individuals and asked them their daily one-way commuting mileage. The results are as follows. Determine whetherornotthevariance inmileage drivenisstatistically thesameamongtheworkingclassandprofessional (middle income) groups. Use a 5% significance level.
Working class Professional (middle incomes) Professional (wealthy)
17.8 16.5 8.5
26.7 17.4 6.3
49.4 22.0 4.6
9.4 7.4 12.6
65.4 9.4 11.0
47.1 2.1 28.6
19.5 6.4 15.4
51.2 13.9 9.3

10. Isthevariancefortheamountofmoney,indollars,thatshoppersspendonSaturdaysatthemallthesameasthevariance fortheamountofmoneythatshoppersspendonSundaysatthemall?
Saturday Sunday Saturday sunday
75 44 62 137
18 58 0 82
150 61 124 39
94 19 50 127
62 99 31 141
73 60 118 73
89