1. A researcher claims that the mean annual cost of raising a child (age 2 and under) by husband-wife families in the U.S. is $13,960. In a random sample of husband-wife families in the U.S., the mean...

1. A researcher claims that the mean annual cost of raising a child (age 2 and under) by husband-wife families in the U.S. is $13,960. In a random sample of husband-wife families in the U.S., the mean annual cost of raising a child (age 2 and under) is $13,725. The sample consists of 500 children. Assume the population standard deviation is $2345. At a = 0.10, is there enough evidence to reject the claim?

2. In Example 10, at a = 0.01, is there enough evidence to reject the claim?

a. Identify the level of significance a.

b. Find the critical values -z0 and z0 and identify the rejection regions.

c. Sketch a graph. Decide whether to reject the null hypothesis.

d. Interpret the decision in the context of the original claim.