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:
x=2
Step-by-step explanation:
-6.5 which in your answer choices is a
Answer:
D) bx - a
Step-by-step explanation:
If a/b is a zero, then (x -a/b) is a factor of the polynomial. That is, the value x=a/b will make a factor of the polynomial be zero.
The above factor can be written without fractions by multiplying it by b:
(bx -a) . . . . matches choice D
__
You can also choose the answer on the basis of which expression becomes zero when x=a/b.
Step-by-step explanation:
y = 23.28/6 x
y = 3.88 x
so, the constant of proportionality is 3.88