Answer:
189 components must be sampled.
Step-by-step explanation:
We have that to find our level, that is the subtraction of 1 by the confidence interval divided by 2. So:
Now, we have to find z in the Ztable as such z has a pvalue of .
That is z with a pvalue of , so Z = 2.575.
Now, find the margin of error M as such
Assume that component lifetimes are normally distributed with population standard deviation of 16 hours.
This means that
How many components must be sampled so that a 99% confidence interval will have margin of error of 3 hours?
n components must be sampled.
n is found when M = 3. So
Rounding up:
189 components must be sampled.