I. Z-TEST USING ONE-SAMPLE MEAN

1. It was claimed that the meanhousehold water usage of customers of a certain community was 45 cubic meters per month. Fifty homes were randomly selected and found that their mean consumption was 47 cubic meters per month with a standard deviation of 2.5 cubic meters. It was agreed that this hypothesis would be subjected to a one-tailed test. Is there enough evidence to accept the claim that the mean household water usage of the customers per month is 45 cubic meters at = 0.01?

II. T-TEST USING ONE SAMPLE MEAN

1. An automotive corporation claimed that one of its brands of cars can travel an average of 32 km. in a gallon of gasoline Consumers' test using 9 cars of the brand resulted to an average consumption of 30 km. in a gallon. with a standard deviation of 2 km. Is the claim true at 1% level of significance? (Use a two-tailed test)

III. Z-TEST USING TWO-SAMPLE MEANS

1. Two sections of Engineering Data Analysis class were given identical instructions to read and study assigned text materials. Two quizzes and a final exam were given during the term, with one section taking quizzes at the beginning of a lecture and the other section taking quizzes at the end. Final exam scores for the two groups are summarized. Do the following data indicate that there is a significant difference in the true mean final scores for students who take quizzes at the beginning of the class and those who take quizzes at the end? Use = 5%.

Statistics	Quizzes at the beginning	Quizzes at the end
Sample size	50	50
Mean	120	110
Standard deviation	25	21

(Use a one-tailed test)

IV. T-TEST USING TWO SAMPLE MEANS

1. A study was conducted to examine the relationship between attitudes towards mathematics and success at college level mathematics. Each student was asked to respond to a series of questions, and then answers were used to obtain a math anxiety. Summary values appear in the table below. Test the hypothesis using a 0.05 level of significance.

Gender

n

\f