Consider the following data on the diameter of a rivet. Assume a normal population.

Question

Consider the following data on the diameter of a rivet. Assume a normal population.

6.68 6.66 6.62 6.72 6.76 6.67 6.70

6.72 6.78 6.66 6.76 6.72 6.76 6.70

6.76 6.76 6.74 6.74 6.81 6.66 6.64

a) Estimate the population variance 𝜎2.

b) Compute a 90 percent two-sided confidence interval for 𝜎2.

c) Compute a value v that enables us to state, with 99 percent confidence, that 𝜎2 is less than v.

Answer 1

A) you must find the sample variance and standard deviation

B) and (c)

(N-2)* var / chi-square

Using the given significant level and 21 d.f