Question

The Ball Corporation's beverage can manufacturing plant in Fort Atkinson, Wisconsin, uses a metal supplier that provides metal with a known thickness standard deviation σ = .000669 mm. Assume a random sample of 52 sheets of metal resulted in an x¯ = .2378 mm. Calculate the 90 percent confidence interval for the true mean metal thickness. (Round your answers to 4 decimal places.) The 90% confidence interval is from to

Answer 1

Solution :

Given that,

Sample size = n = 52

Z/2 = 1.645

Margin of error = E = Z/2* ( /n)

= 1.645 * (.000669 / 52)

Margin of error = E = .0002

At 90% confidence interval estimate of the population mean is,

- E < < + E

.2378 - .0002 < < .2378 + .0002

.2376 < < .2380

The 90% confidence interval is from .2376 to .2380