[EX02-194] The volume of Christmas trees sold annually in the United States has declined in recent decades according to a USDA National Agricultural Statistics Service report. All 50 states report contributions to the total U.S. sale of about 25 million Christmas trees annually. Furthermore, each state reports its crop by county. The top 20 producing counties in the United States come from seven states. The number of trees sold by the top 20 counties in 2002 are listed in the following table. This survey is done every 5 years.

Number of Christmas Trees Sold by County (10,000s)

42.8 25.4 84.8 36.5 16.7 21.3 87.6 65.4 140.0 15.2 41.2 17.2 15.0 103.0 22.1 25.6 20.3 259.0 64.2 19.1 Source: USDA National Agricultural Statistics Service

a. Calculate the mean, median, and midrange for the number of Christmas trees sold annually by the 20 top producing counties.

b. Calculate the standard deviation.

c. What do the answers to parts a and b tell you about the distribution for the number of trees?

Explain.

d. Notice that the standard deviation is a larger number than the mean. What does that mean in this situation?

e. Draw a dotplot of the data.

f. Locate the values of the answers to parts a and b to the dotplot drawn for part e.

g. Answer parts c and d again, using the information learned from the dotplot.