Standard Deviation and Confidence Intervals

Instructions: Use the formulas and procedures provided in the Basic Statistics Review module to SOLVE the following business problems and ANSWER the associated questions.

The following data represent the average 2020 monthly sales in thousands of euros () for ALL sales teams in the Europe, Middle East, and Africa (EMEA) region of QualCase, Inc. Use the numbers shown in the table for your calculations (omitting the thousands).

Month	Units sold (000) (xi)	(x x-bar)	Squared values	Divide total by n-1	SQRT
Jan	784			|	|
Feb	885			|	|
Mar	775			|	|
Apr	954			|	|
May	893			|	|
Jun	822			|	|
Jul	765			|	|
Aug	704			|	|
Sep	888			|	|
Oct	954			|	|
Nov	852			|	|
Dec	907			V	V
TOTAL =>		TOTAL =>
n =				^ VARIANCE	^ STANDARD DEVIATION
x-bar =

PROBLEM #1 (330 points): 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 in euros (000)?

PROBLEM #2 (330 points): Apply the results of your answer from 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 in the EMEA region? BE SURE TO SHOW ALL YOUR WORK.

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

PROBLEM #3 (340 points): QualCase, Inc. issues an Annual Consistency Bonus to regions that keep their average monthly sales production for protective cases above 850 units with a confidence level of 95%. Based on your answers to the first two problems, DOES THE EMEA TEAM QUALIFY for the Annual Consistency Bonus?

BE SURE TO USE THE INPUTS IN THE QUESTIONS AND THE RESULTS OF YOUR CALCULATIONS TO EXPLAIN WHY OR WHY NOT.