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.
I’ve attached my work below for #4
5) 8% is equivalent to 8 cents so each item was $1.08
Than you know he spent 16.20 so you divided
1.08/16.20 which equals 15
So he got 15 items
6) the moon is 250,000 miles away which is about driving around earth 10 times which would take 6 months (not sure about this one)
Hope this helps!
Have a nice day :)
Answer:
(3,5)
Step-by-step explanation:
The correct answer should be B.