Directions: In exercises asking to test a claim, use the five-step hypothesis-te

Question

Directions: In exercises asking to test a claim, use the five-step hypothesis-testing proce- dure. Give either the P-value or the critical region. Unless otherwise specified, use a 0.05 significance level. 1. Supervisors at a company that manufactures baseball bats have retooled some machinery in an attempt to reduce variation in the weights of the bats. Before retooling, a sample of 41 bats had a standard deviation of 1.24 oz. After retooling, a sample of 61 bats had a standard deviation of 0.54 oz. Assuming that both populations are normally distributed, test the claim that the variance before retooling is higher than the variance after retooling. Does the retooling appear to have worked?

Explanation / Answer

1)

Rcode:

var.test(x,y, alternate= "greater")

where x = sample 1

y = sample 2

To perform variance test in R, you should have sample data. With just standard deviation, we cannot perform variance test in R.

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