Question

Hen 430 randomly selected light bulbs were tested in a laboratory, 224 lasted more than 500 hours. Find a point estimate of the last more than 500 hours proportion of all light bulbs thatA 0.479B 0.343C 0.519D 0.521

Answer 1

By the definition, An observed value of \bar{x} to estimate the mean of population is a point estimate and the statistic \bar{x} is a poiont estimator.

It is given that, "Hen 430 randomly selected light bulbs were tested in a laboratory"

That is, the Random sample size n= 430

The statement given that, "224 lasted more than 500 hours"

So x=224

Now find a point estimate of the last more than 500 hours proportion of all light bulbs:

Thus $p=\frac{x}{n}=\frac{224}{430}$

This implies that $p=0.5209\sim0.521$

Thus the answer is D: 0.521.