## A polymer is manufactured in a batch chemical process. Viscosity measurements show that it is approximately normally distributed with a sta

Question

A polymer is manufactured in a batch chemical process. Viscosity measurements show that it is approximately normally distributed with a standard deviation of 20. A random sample of 42 batches has a mean viscosity of 759. Construct a 99% confidence interval around the true population mean viscosity.

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2021-10-10T23:04:42+00:00
2021-10-10T23:04:42+00:00 1 Answer
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## Answers ( )

Answer:(751.05, 766.95)Step-by-step explanation:We know that the

confidence interval for population meanis given by :-,

where =population standard deviation.

= sample mean

n= sample size

z* = Two-tailed critical z-value.

Given :n= 42

We know that from z-table , the two-tailed critical value for 99% confidence interval : z* =2.576

Now, the 99% confidence interval around the true population mean viscosity :-

∴ A 99% confidence interval around the true population mean viscosity :(751.05, 766.95)