Question

the lifetime of a certain type of battery is known to be normally distributed with standard deviation σ=22 hours. a sample of 50 batteries had a mean lifetime of 120.1 hours. it is desired to construct a 95% confidence interval for the mean lifetime for this type of battery.
part: 0 / 6
part 1 of 6
(a) what is the point estimate?
the point estimate is .

Explanation:

Step1: Recall point estimate definition

The point estimate for the population mean \(\mu\) is the sample mean \(\bar{x}\).

Step2: Identify sample mean from problem

The problem states the sample of 50 batteries had a mean lifetime of 120.1 hours. So the sample mean \(\bar{x} = 120.1\), which is the point estimate for the population mean.

Answer:

120.1