Summary Measures

Exercise 6.1 

Open the Excel workbook Exa 8.1B.xlsx from the Exercises folder. Obtain the sample size, sample mean weight loss and the sample standard deviation of the weight loss for Diet B. Place these results in the block of cells F23 to F25, using the same format as that employed for the Diet A results in the above example.

Briefly interpret your findings. What do these results tell you about the relative effectiveness of the two weight-reducing diets?

The sample size for diet B is 50
The diet B hasn't been as effective as the diet A: 3.710
The standard deviation or proportion of people losing weight is less in B than in the A group

Exercise 6.2 

Open the Excel workbook Exa 8.2B.xlsx from the Exercises folder. Obtain the sample median, first and third quartiles and the sample interquartile range of the weight loss for Diet B. Place these results in the block of cells F26 to F29, using the same format as that employed for the Diet A results in the above example.

Briefly interpret your findings. What do these results tell you about the relative effectiveness of the two weight-reducing diets?

Diet B
The sample median weight loss is M = 3.745 kg, this mean that the diet had a positive effect but less that diet A.

The sample interquartile range of the weight loss is IQR = 3.451 kg. A lower proportion of those individuals on Diet B had a positive weight loss, meaning that the difference between the individual losing more weight and the one losing less weight is greater.

Exercise 6.3

Open the Excel workbook Exa 8.3D.xlsx from the Exercises folder. Obtain the frequencies and percentage frequencies of the variable Brand, but this time for the Area 2 respondents, using the same format as that employed for the Area1 results in the above example.
Briefly interpret your findings. What do these results tell you about the patterns of brand preferences for each of the two demographic areas?

In the Area 2
Frequencies
Out of 79 respondents
19 prefered Brand A
30 prefered Brand B
30 prefered Other brands


Percentages
Out of 79 respondents
24.1% prefered Brand A
38.0% prefered Brand B
38.0% prefered Other brands