Statistics Test 3a Prof. VanderHoff Spring 2003

All work must be shown on exam to receive credit.

1. [15] Test the null hypothesis that the mean of X = the mean of Y. Use a .01 significance level, a two tail test and the following data:

X Y

8 3

7 5

3 8

-1 7

0 -1

2. [10] Test the null hypothesis that the proportion of voters favoring GW Bush is 70% [p=.7; the alternative hypothesis is: p>.7.]. A sample of 550 voters has 400 Bush supporters. Use α=.05

3. [15] Test the null hypothesis that the mean for men = the mean for women. Use a two tail test and a significance level of .10.

men women

Sample size 67 51

Mean 59 56

stand. Dev. 9 8

4. [10] Test the hypothesis that the mean=35 Use a two tail test and a significance level=.01. A sample of 8 has a mean=43 and a standard deviation=12.

5. [15] Test if drinking pop helps driving scores higher on tests. Use a two tail test and a .10 significance level. The scores of 6 drivers before and after they drink pop are:

Driver before after

1 3 2

2 4 5

3 9 3

4 5 2

5 7 3

6 8 3

6. [15] Groups of men and women were asked if they enjoyed statistics. Using the data below, test the hypothesis the proportion enjoying statistics is the same for both groups. Use a two tail test and a significance level of.05.

Men women

Enjoy stats 220 50

Number asked 400 120

7. [10] Test if the average weight is 45 lbs. Use a one tail test [the alternative hypothesis is that the average is less than 45 lbs.] and a significance level of .05. A sample of 49 has a mean=47 and a standard deviation=9.

8. [10] A sample of 9 students has an average parking tickets per year equal to 59.. The standard deviation = 6. Use a two tail test and a .05 significance level to test the hypothesis the average number of tickets among all students is 55.