The following data represent the 2019 monthly sales in units for the Pacific Region Sales Team of QualCase, Inc.

Month	Units sold (xi)	(x x-bar)	Squared values	Divide total by n-1	SQRT
Jan	73			|	|
Feb	79			|	|
Mar	76			|	|
Apr	79			|	|
May	80			|	|
Jun	78			|	|
Jul	77			|	|
Aug	78			|	|
Sep	75			|	|
Oct	72			|	|
Nov	75			|	|
Dec	82			V	V
TOTAL =>		TOTAL =>
n =
x-bar =

PROBLEM #1: Use the table above and the procedures learned in class to calculate the standard deviation (notated as s) of average monthly sales. What is the standard deviation of average monthly sales?

PROBLEM #2: Apply the results of your answer to Problem #1 and use the table below and the procedures learned in class to calculate the 95% confidence interval for average monthly sales in units. What is the 95% confidence interval (CI) for average monthly sales?

SE of mean
z-value	1.96
Plus/minus value
Upper CI value
Lower CI value