Answer:
$4.55
Step-by-step explanation:
7% of $65 = $4.55
defective : working = 1/15 ( x20 ) 20/300
so the answer is 20 light bulbs
Answer:
a. Assume that the population has a normal distribution.
b. The 90% confidence interval of the mean sale time for all homes in the neighborhood is between 219.31 days and 240.69 days.
Step-by-step explanation:
Question a:
We have to assume normality.
Question b:
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 = 1.645.
Now, find the margin of error M as such

In which
is the standard deviation of the population and n is the size of the sample.

The lower end of the interval is the sample mean subtracted by M. So it is 230 - 10.69 = 219.31 days.
The upper end of the interval is the sample mean added to M. So it is 230 + 10.69 = 240.69 days.
The 90% confidence interval of the mean sale time for all homes in the neighborhood is between 219.31 days and 240.69 days.
The answer to your question is 200.
100%-40%=60%
60%=120 students
60%÷3=20%
120÷3=40
20%=40
20%X5=100%
40X5=200