The accompanying frequency distribution summarizes data on the number of times smokers who had successfully quit smoking attempted to quit before their final successful attempt (“Demographic Variables, Smoking Variables, and Outcome Across Five Studies,”

Health Psychology [2007]: 278–287).

Number of Attempts Frequency 0 778 1 306 2 274 3–4 221 5 or more 238 Assume that no one had made more than 10 unsuccessful attempts, so that the last entry in the frequency distribution can be regarded as 5–10 attempts. Summarize this data set using a histogram. Be careful—the class intervals are not all the same width, so you will need to use a density scale for the histogram. Also remember that for a discrete variable, the bar for 1 will extend from 0.5 to 1.5. Think about what this will mean for the bars for the 3–4 group and the 5–10 group.