1. Damian has a balance of $10,200 on his credit card. He threw the card away so he can never use it again. He has 3.5 years to pay off the balance. The interest rate on his card is 21%. At the end of the 3.5 years, how much interest has he paid? 2. When Damian pays off his credit card, how much he will have paid in all?

The minimum sample size is 198

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 the margin of error M as such

In which is the standard deviation of the population and n is the size of the sample.

What is the minimum sample size required to estimate a population mean with 95% confidence when the desired margin of error is E=1.5?

This sample size is n.

n is found when M = 1.5.

We have that

Rounding up

The minimum sample size is 198