# The normally distributed AAA battery life is stated to be 350 days when used in a clock radio. - 6550

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The normally distributed AAA battery life is stated to be 350 days when used in a clock radio. The Big Charge Battery Company has recently modified the AAA batteries so as to extent their life. The owner of the company wanted to know if the improved batteries really did last significantly longer. A sample of 100 of the improved batteries was tested. It was discovered that the mean life was 362 days and the sample standard deviation was 10 days. The research department decided to conduct the test at the 0.05 level of significance whether the modification actually increased the life of the AAA battery. What was their decision rule?

A.   Reject the null hypothesis if computed z is less than 1.96. B.   Do not reject the null hypothesis if computed z is 1.65 or greater. C.   Do not reject the null hypothesis if the z test statistics is 1.96 or greater.

D.   Reject the null hypothesis if computed z is 1.96 or greater.

3) What is the critical value for a two-tail, one sample hypothesis test in which a null hypothesis is tested at the 5% level of significance based on a sample size of 23?

A.   2.074

B.   1.717

C.   2.069

D.   1.714

Solution Description

The normally distributed AAA battery life is stated to be 350 days when used in a clock radio. The Big Charge Battery Company has recently modified the AAA batteries so as to extent their life. The owner