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: The answer is b 100+(-500)
Step-by-step explanation: If you solve for the original and this answer, they will both equal -400
26>-9
This states that 26 is greater than -9. Look at the > sign like it's an alligator's mouth - the alligator wants to eat the bigger side, and 26 is clearly bigger than -9, so the alligator wants to eat 26!