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).
9514 1404 393
Answer:
3 months
Step-by-step explanation:
We don't know what's on your list of "useful financial formulas." One that can be used here is the formula for simple interest:
I = Prt . . . . . interest on principal P at annual rate r for t years
Solving for t gives ...
t = I/(Pr)
Filling in the given values, we can find t to be ...
t = 138/(4800×0.115) = 138/552 = 1/4
1/4 year is 3 months -- the duration of the loan.
Answer:
114
Step-by-step explanation:
15 x 2 + 9 x 2 + 11 x 3 + 11 x 3 = 114
(the bottom portion is equal to 3 x 11)
Answer:
7
Step-by-step explanation:
Substitute the value of the variable into the expression and simplify
