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:
2b+t/2=a
Step-by-step explanation:
3a + 4b = 5a-t
-3a -3a
4b = 2a - t
+t +t
4b + t = 2a
/2 /2
2b+t/2=a
Answer:
i thought this was a meme bro
Step-by-step explanation:
Answer:
Ali's salary is $50000.
Step-by-step explanation:
Let Jafar's salary be x.
(31/100)*x = 12400
x = (12400*100)/31
x = 400*100
x = $40000
Let Ali's salary be y.
y-[(20/100)*y] = 40000
y-(y/5) = 40000
(5y-y)/5 = 40000
4y = 200000
y = $50000