Question

1. a weatherman records the amount of rain that fell in portland, oregon each day for a year. what type of graph should he use to show how rainfall changes during the year? a) pie graph b) pictograph c) time series graph d) pareto chart 15. find the class with the least number of data values. a) 55 - 65 b) 65 - 75 c) 75 - 85 d) 85 - 95 16. an ogive is also called a cumulative frequency graph. t f 17. the frequency polygon and the histogram are two different ways to represent the same data set. t f 18. for a given data set, the ogive and the frequency polygon will have the same overall shape. t f 19. a pareto chart is useful for showing percentages of the total at different times. t f 20. the frequency polygon is a graph that displays the data by using lines that connect points plotted for the frequencies at the midpoints of the classes. t f 21. a histogram is a graph that represents the cumulative frequencies for the classes in a frequency distribution. t f 22. if the limits for a class were 20 - 38, the boundaries would be 19.5 - 38.5. t f

Explanation:

1. A time - series graph is used to show how a variable changes over time. Since we want to see how rainfall changes during the year (time - based data), a time - series graph is appropriate. Pie graphs show proportions of a whole, pictographs use pictures to represent data, and Pareto charts are used to show the relative importance of different factors.
2. By observing the bar - chart, the class 85 - 95 has the lowest frequency (height of the bar), so it has the least number of data values.
3. An ogive is indeed a cumulative frequency graph.
4. A frequency polygon and a histogram can represent the same data set, where the frequency polygon is formed by connecting the mid - points of the tops of the histogram bars.
5. The ogive and the frequency polygon do not have the same overall shape. The ogive is a cumulative frequency graph and the frequency polygon represents the frequencies at mid - points.
6. A Pareto chart is used to rank data from most to least important, not for showing percentages of the total at different times.
7. A frequency polygon is a graph that uses lines to connect points plotted for the frequencies at the mid - points of the classes.
8. A histogram represents the frequencies of classes in a frequency distribution, not cumulative frequencies.
9. To find class boundaries, we subtract 0.5 from the lower class limit and add 0.5 to the upper class limit. For the class 20 - 38, the boundaries are 19.5 - 38.5.

Answer:

1. C. time series graph
2. D. 85 - 95
3. T
4. T
5. F
6. F
7. T
8. F
9. T