Exam 3: Graphical Methods for Describing Data

The quantity often gives a rough estimate of the appropriate number of intervals in a histogram.

Would you say that most lawyers in this country are really interested in the public good, or are most lawyers just out to make a lot of money? The following table summarizes the responses to the lawyer question when these questions were asked in different orders. (a) Construct a comparative bar chart for these response percentages. (b) Interpret the results of the 1974 survey. Do you think the order of the questions made a difference in the responses? Explain.

As part of the United States Census, data is also collected on the number of persons in each household. The census data for four decades is summarized below. (a) In a few sentences describe how the proportion of households with 4 people has changed from 1970 to 2000. (b) What size of household appears to have decreased the most from 1970 to 2000?

In a scatter plot, both the horizontal and vertical axes must be set at zero.

In 1986 marine biologists reported the discovery of a new species of fish in the Western North Atlantic. Data on the head length (n = 41) and pelvic fin length (n = 30) are shown below. a) Describe in appropriate statistical terms, the distributions of these two variables. b) The distribution of head lengths certainly appears to be rather strange. What do you think might account for the shape of this distribution?