The sum of 21 and Matt's age is 44.
Use the variable m to represent Matt's age.

m=23

Step-by-step explanation:

21+m=44

subtract 21 from both sides

m=23

(a)

(b) The best  point estimate of is the sample mean

The margin of error =  4.552

Step-by-step explanation:

Given : The confidence interval for the population mean =  (13.046 , 22.15)

Sample mean :

Standard deviation :

Sample size :

a. Let represents the population mean.

Then we can write the confidence interval for the population mean as :-

b. The best  point estimate of is the sample mean

Also, the lower limit of confidence interval can be written as

i.e.

Hence, the margin of error =  4.552