1. MEDICO Corporation makes several portable electronic devices used in hospitals. Some of these products require rechargeable batteries that MEDICO purchases from various suppliers. Although they try to find them at the best price, they must also consider the quality. In one case, two suppliers were being considered, and batteries were selected from various purchase dates. A test was run on the time the batteries would last in a certain device before it had to be recharged. The results are given in the table below.

Sample Statistics for Survey of Batteries

Supplier Number of Batteries Used in Test Mean Life Standard Deviation

Power+ 45 24 hours 5.1 hours

Electro 61 22 hours 2.6 hours

a) Set up the null and alternative hypotheses to see if the data supports the conclusion that the rechargeable batteries sold byPower+last longer.

b) Check the conditions.

c) Calculate the test statistic.

d) Find the p-value.

e) Using = 0.05, state your conclusion in the context of the problem.

2.A construction company that installs drywall wanted to investigate how a person's age affects how much dry wall they can install in a week. On one hand, it would seem that the younger workers would be able to install more, but it seems that experience would also play a role. Two random samples were taken. Assume the distributions are normal.

Dry Wall Results by Age

Age 18-21

(sheets/week)

92

109

93

81

115

109

84

121

94

116

Age 25-28

(sheets/week)

104

116

96

104

108

108

116

112

120

108

a) Set up the null and alternative hypotheses to see if there is a difference in the average number of sheets of dry wall that a person can install per week based on age.

b) Check the conditions.

c) Calculate the test statistic.

d) Find the p-value.

e) Using = 0.05, state your conclusion in the context of the problem.