# Question

A random sample of 21 nickels measured with a very accurate micrometer showed a mean diameter of 0.834343 inch with a standard deviation of 0.001886 inch.

(a) Why would nickel diameters vary?

(b) Construct a 99 percent confidence interval for the true mean diameter of a nickel.

(c) Discuss any assumptions that are needed.

(d) What sample size would ensure an error of ±0.0005 inch with 99 percent confidence? (Data are from a project by MBA student Bob Tindall.)

(a) Why would nickel diameters vary?

(b) Construct a 99 percent confidence interval for the true mean diameter of a nickel.

(c) Discuss any assumptions that are needed.

(d) What sample size would ensure an error of ±0.0005 inch with 99 percent confidence? (Data are from a project by MBA student Bob Tindall.)

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