Statistical analysis

Question 1
Missy Walters owns a mail-order business specializing in clothing, linens, and furniture for
children. She is considering offering her customers a discount on shipping charges for
furniture based on the dollar-amount of the furniture order. Before Missy decides the
discount policy, she needs a better understanding of the dollar-amount distribution of the
furniture orders she receives.
Missy had an assistant randomly select 50 recent orders that included furniture. The
assistant recorded the value, to the nearest dollar, of the furniture portion of each order. The
data collected is listed below (data set also provided in accompanying MS Excel file).
136 281 226 123 178 445 231 389 196 175
211 162 212 241 182 290 434 167 246 338
194 242 368 258 323 196 183 209 198 212
277 348 173 409 264 237 490 222 472 248
231 154 166 214 311 141 159 362 189 260
a. Prepare a frequency distribution, relative frequency distribution, and percent
frequency distribution for the data set using a class width of $50.

b. Construct a histogram showing the percent frequency distribution of the furnitureorder values in the
HI6007 T12018 Group Assignment Page 2
Question 2
Shown below is a portion of a computer output for a regression analysis relating Y (demand)
and X (unit price).
df SS
Regression 1 5048.818
Residual 46 3132.661
Total 47 8181.479
Coefficients Standard Error
Intercept 80.390 3.102
X -2.137 0.248
a. Determine whether or not demand and unit price are related. Use a = 0.05.

b. Compute the coefficient of determination and fully interpret its meaning.
Be very specific.
c. Compute the coefficient of correlation and explain the relationship between
demand and unit price.

Question 3 6 marks
The following are the results from a completely randomized design consisting of 3
Source of Variation
Sum of
Degrees of
Square F
Between Treatments 390.58
Within Treatments (Error) 158.40
Total 548.98 23
Using a = .05, test to see if there is a significant difference among the means of the three
populations. The sample sizes for the three treatments are equal.
HI6007 T12018 Group Assignment Page 3
Question 4 10 marks
In order to determine whether or not the number of mobile phones sold per day (y) is related
to price (x1 in $1,000), and the number of advertising spots (x2), data were gathered for 7
days. Part of the Excel output is shown below.
df SS MS F
Regression 40.700
Residual 1.016
Coefficients Standard Error
Intercept 0.8051
x1 0.4977 0.4617
x2 0.4733 0.0387
a. Develop an estimated regression equation relating y to x1 and x2. (2 marks)
b. At a = 0.05, test to determine if the estimated equation developed in Part a represents
a significant relationship between all the independent variables and the dependent variable.
(2 marks)
c. At a = 0.05, test to see if ß1 and ß2 is significantly different from zero. (2 marks)
d. Interpret slope coefficient for X2. (2 marks)
e. If the company charges $20,000 for each phone and uses 10 advertising spots, how
many mobile phones would you expect them to sell in a day?

Sample Solution