There is a Khana Academy video that explains everything you have to do and it’s the same page that you’re on
Answer:
The 98% confidence interval for the mean purchases of all customers is ($37.40, $61.74).
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
.
So it is z with a pvalue of
, so 
Now, find 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 mean subtracted by M. So it is 49.57 - 12.17 = $37.40.
The upper end of the interval is the mean added to M. So it is 49.57 + 12.17 = $61.74.
The 98% confidence interval for the mean purchases of all customers is ($37.40, $61.74).
Answer:
(1/5)x-5.4=y
Step-by-step explanation:
mx+b=y
m=(1/5)
(-8,-7)=(x,y)
(1/5)(-8)+b=(-7)
-1.6+b=-7
b=-5.4
(1/5)x-5.4=y
Answer:
x=4
Step-by-step explanation: