Multiply the second fraction by three.
4/9 + 3/9 = 7/9
Answer:
Margin of error of 0.0485 hours.
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 = 1.96.
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.
In this question:

The margin of error is of:



Margin of error of 0.0485 hours.
Answer:
8. 12 in
9. 30 ft
10. 87.92 in
Step-by-step explanation: