Blogs for Fortune 500 firms. Web site communication through blogs and forums is a key marketing tool for companies. The Journal of Relationship Marketing (Vol. 7, 2008) investigated the prevalence of blogs and forums at Fortune 500 firms with both English and Chinese Web sites.

a. Of the firms that provided blogs/forums as a marketing tool, the accompanying table gives a breakdown on the entity responsible for creating the blogs/forums. Use a graphical method to describe the data summarized in the table. Interpret the graph.

b. In a sample of firms that provide blogs and forums as marketing tools, the mean number of blogs/forums per site was 4.25, with a standard deviation of 12.02. Provide an interval that is likely to contain the number of blogs/forums per site for at least 75% of the Fortune 500 firms in the sample.

c. Do you expect the distribution of the number of blogs/ forums to be symmetric, skewed right, or skewed left? Explain.

a. In the above table, the stem is the portion of measurement to the left of the decimal point and the leaf is the portion of measurement to the right of the decimal point. We can say that the maximum number of blogs/forums were created by companies with a percentage of 38.5 and the minimum number of blogs/forums were created by third parties. A total of 73% of blogs/forums were created by companies and employees together.

b. In the question the mean is given as 4.25 and the standard deviation as 12.02. We know that 75% of the measurements will lie within 2 standard deviations of the mean, therefore we will calculate the interval as,

$$\begin{gathered} (4.25-2\times 12.02,4.25+2\times 12.02) \\ =(-19.79,28.29) \\ =(0,28.29) \end{gathered}$$

Therefore, the interval that is likely to contain the number of blogs/forums per site for at least 75% of the Fortune 500 firms in the sample is (0, 28.29).

c. The distribution of the number of blogs/forums is skewed to the right. Since the standard deviation is larger than the mean, therefore we can say that the mean will also be greater than the median and therefore the distribution will be skewed to the right. This also means that the right tail of the observation has more extreme observations which tend to pull the mean away from the median.