Battery life for a hand-held computer is normally distrituted and has a population standard deviation of 8 hours. suppose you need to estimate a confidence interval estimate at the 80% level of confidence for the mean life of these batteries. determine the sample size required to have a margin of error of 0.332 hours. round up to the nearest whole number

Sample size= 956

Step-by-step explanation:

Hello!

You need to construct an 80% CI for the average life of batteries. (hours)

The study variable is:

X: Lifespan of a battery.

X~N(μ; σ²)

The population standard devition isσ= 8

The interval to estimate the population mean follows the structure:

"Point estimator" ± "margin of error"

X[bar] ± * (σ/√n)

X[bar] is the sample mean

* (σ/√n) is the margin of error of the interval (d)

Using the margin of error you can calculate the sample size:

d= * (σ/√n)

n= (σ* )²

n=

n= 955.77 ≅ 956

I hope it helps!

the sum of all the angles in a triangle are equal to 180

so you can add   the 3 given angles together to equal 180:

5y + 2y + 2y = 180

or since all three angles have the same letter, combine the 3 angles to equal 180:

9y = 180