A confidence interval,at the95%confidencelevel,willbe used to answer the question,"What is the mean annual salary (in US dollars) of a Tesla car owner?"Data was collected from36Tesla owners across the US.The meanannual salary of those36Tesla owners was$289000.The standard deviation of ALL Tesla owners is known to be$1342.

a)The value at the center of the confidence interval represents what quantity?Choose an option from the list and type its corresponding letter in the box.

1. population mean
2. sample mean
3. standard deviation
4. sample size

Answer for (a):sample mean

b)Isz*or t*used when building thisconfidenceinterval?Choose an option from the list and type its correspondingletter(A or B)in the box.

1. z*
2. t*

Answer for (b):t*

c)Determine the value of the letter indicated in part(b)using one of the following tables:normal table,t table.Type the number, recorded to3decimals, in the box.

Answers for (c):

**** how do I use the table and which one should I be using? I don't think I have the previous answer correct but I don't know which one should be chosen or why.****

e)If the sample size is decreased to 20 Tesla owners, what would happen to theconfidence interval?Choose an option and write its corresponding letter the blank below.

1. It widens.
2. It does not change.
3. It narrows.

Answer for (e):I believe it widens, but why?