Apolymer 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.

(751.05, 766.95)

Step-by-step explanation:

We know that the confidence interval for population mean is 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)

answer

d. 10

explanation

the distance from point y to wx is the height of the triangle.

using pythagoras theorem,

group similar terms to get,

this implies that,

take positive square root of both sides to get,

this implies that,

70

step-by-step explanation: