The article The Distribution of Buying Frequency Rates

Chapter 0, Problem 7.90

(choose chapter or problem)

The article The Distribution of Buying Frequency Rates (Journal of Marketing Research [1980]: 210216) reported the results of a -year study of dentifrice purchases. The investigators conducted their research using a national sample of 2071 households and recorded the number of toothpaste purchases for each household participating in the study. The results are given in the following frequency distribution: Number of Number of HousePurchases holds (Frequency) 10 to 20 904 20 to 30 500 30 to 40 258 40 to 50 167 50 to 60 94 60 to 70 56 70 to 80 26 80 to 90 20 90 to 100 13 100 to 110 9 110 to 120 7 120 to 130 6 130 to 140 6 140 to 150 3 150 to 160 0 160 to 170 2 31 2 7.7 C a. Draw a histogram for this frequency distribution. Wouldyou describe the histogram as positively or negativelyskewed?b. Does the square-root transformation result in a histogramthat is more symmetric than that of the originaldata? (Be careful! This one is a bit tricky, because youdont have the raw data; transforming the endpoints of theclass intervals will result in class intervals that are notnecessarily of equal widths, so the histogram of the transformedvalues will have to be drawn with this in mind.)