Express the confidence interval in the format that uses the "less than" symbol. given that the original listed data use one decimal place, round the confidence interval limits accordingly.

(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