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).
The surveyor selects the twentieth student who enters the building. The student do not enter the building to be surveyed but for other reasons and the researcher take advantage of that and selects them. This is a form of continence sampling.
The researcher selects every twentieth student and not any other. Therefore, the sampling is systematic in nature.
Finally, students selected to participate in the survey are free to choose if to participate in he survey or not. Therefore, it is voluntary kind of sampling.
Therefore, the applicable sampling methods are convenience, systematic, and voluntary.
You need to divide 658 by 120 because you know one gallon covers 120 square feet.
Answer:
She bought 5 pounds.
Step-by-step explanation:
if she spent 10 dollars and its 2 dollars per pound that means that you have to divide 10 by 2 in order to get how many pounds you can buy for 10 dollars.
If you think about it if you want 2 pounds then you multiply 2 by 2 to get four because its 2 dollars per pound and you need 2 pounds. so since you don't know the number of pounds you fill in the blanks and do 10/2 to get 5.
