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Finding confidence Intervals for Toner

A manufacturer would like to estimate the average number of copies that can be made from a single bottle of toner. A random sample of 20 bottles was selected for this experiment. For the 20 bottles of toner the average number of pages was 1535 with a standard deviation of 50 pages.

a) Compute the 95% confidence interval for the average number of pages that can be made from a single bottle of toner. Interpret this interval.

b) How many bottles should be sampled in order to be 95% confident of being within 20 pages of the population mean number of pages per bottle?

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Solution:

a)
Here n =sample size=20

Since sample size is less than 30, and population standard deviation is not known, we will use t statistics. First step will be to estimate the population standard deviation with sample standard deviation .i.e.

Estimated ...

Solution Summary

Solution describes the steps in finding out the confidence interval for number of pages a bottle of toner can copy. It also explains how to find out the sample size for given tolerance.

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