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).
D because those options do not intersect and are part of the universal set
240 because 8 times 30 equals 240
Answer:
189.271 in expanded form is (1 x 100) + (8 x 10) + (9 x 1) + (2/10) + (7/100) + (1/1000)
Step-by-step explanation: hope this helps <3
I=PRT
P=present amount
R=rate
T=time
basically
20+interest<u /> is more than or equal to 400
20+I<u>></u>400
minus 20 both sides
I<u>></u>380
solve
P=20
R=3%=0.03
T=?
I=PRT
380<u><</u>I=PRT
380<u><</u>20(0.03)(T)
380<u><</u>0.6T
divide both sides by 0.6
633.33333<u><</u>T
633.33 years at least
