# Question: A random sample of 21 nickels measured with a very

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.)

**View Solution:**## Answer to relevant Questions

A random sample of 10 miniature Tootsie Rolls was taken from a bag. Each piece was weighed on a very accurate scale. The results in grams were (a) Construct a 90 percent confidence interval for the true mean weight. (b) What ...8.67 Sixteen owners of 2010 Audi A4 sedans kept track of their average fuel economy for a month. The results are shown below. (a) Construct a 95 percent confidence interval for the mean. (b) What factor(s) limit the ...A random sample of 30 lunch orders at Noodles and Company showed a standard deviation of $5.31. Find the 90 percent confidence interval for the population standard deviation. Use Excel to obtain X2L = CHISQ.INV(α/2,d.f.) ...Junior Achievement and Deloitte commissioned a "teen ethics poll" of 787 students aged 1318, finding that 29 percent felt inadequately prepared to make ethical judgments. (a) Assuming that this was a random sample, find ...Find a confidence interval for assuming that each sample is from a normal population. a. x-bar = 14, σ = 4, n = 5, 90 percent confidence b. x-bar = 37, σ = 5, n = 15, 99 percent confidence c. x-bar = 121, σ = 15, n = 25, ...Post your question