Business statistics

Assignment 1 Due 13 Dec 2019

Q1 The Human Resources Manager of a small company is investigating use of and satisfaction with the staff canteen. He decides to run a small survey of staff members.

(a) Suggest two categorical questions that could be asked in the survey, one nominal and one ordinal.

(b) Suggest two numerical questions that could be asked in the survey, one discrete and one continuous.

(c) The Manager is considering distributing the survey by leaving copies on the tables in the canteen, and placing a box at the exit for the completed surveys to be posted.

Discuss briefly any disadvantages of this method, and suggest an alternative.

Q2 The data file Carseats.xls contains information on a company’s sales of child carseats at a number of different locations. The “Info” tab in the worksheet gives a list of the variables and their meanings.

(a) Construct a % frequency distribution for the sales and use this to complete the table below: [3]

Frequency Table for Sales of Car Seats

Sales (in 1000s)	Midpoint	Frequency	% Frequency
0 < x ≤ 2
2< x ≤ 4
4< x ≤ 6
6< x ≤ 8
8< x ≤ 10
10< x ≤ 12
12< x ≤ 14
14< x ≤ 16
16< x ≤ 18

(b) In Excel, construct a histogram illustrating the frequency distribution, and insert this into your assignment. Comment on what it shows. [6]

(c) Calculate summary statistics for the data and use them to complete the table below, rounding your answers to 2 decimal places:

Statistic	Sales (1000s)
Mean
Median
1st quartile
3rd quartile
Interquartile range
Range
Standard deviation

[3]

(d) Using the appropriate variables in Carseat.xls, draw side-by-side boxplots to examine the effect of shelf location on sales. Comment on what they show.

Q3 Refer back to the file Carseat.xls used in Question 2.

(a) Construct a pivot table with Urban as the row variable and Shelf Location as the column variable .... [2]

(b) Use your pivot table to construct a contingency table showing percentages in each shelf location category by urbanity. This means that each row of your table should add up to 100%. [3]

(c) Construct a suitable chart to illustrate the above table, and comment on what it suggests. [4]

Q4 Extension Question – this is not compulsory, but is an opportunity to earn some bonus marks if you want to attempt this more challenging question. You can get up to 5 extra marks by doing so.

Refer back to the data in the file Carseats.xls . Use Excel’s PivotTable facility to create a table showing how the mean and standard deviation of sales vary according to shelf location. You will have to explore the options in the PivotTable Field List in order to change the value field setting from “Sum” (the default) to more appropriate settings. Comment on what your table shows, in relation to your answer to Q2(d).

+ + + + + +

Nominal: Type your answer here

[1]

Ordinal: Type your answer here

[1]

Discrete: Type your answer here

[1]

Continuous: Type your answer here

[1]

Type your answer here

[4]

[4]

[4]

Insert your histogram here

Comment on what it shows here:

Insert your boxplots here

Comment on what they show here:

[4]

Insert your table here

Insert your table here

Insert your chart here

Type your comments here

Insert your table here

Insert your comments here

[5]