Exam 1: Describing Data With Graphs

Compared to the frequency distribution, the stem-and-leaf plot provides more detail, since it can describe the individual data values and show how many are in each group, or stem.

Potato Preferences A study was performed to examine preferences for various types of potatoes: mashed, french fries, hash browns, steak fries, and baked. The following data were recorded regarding the preferences of 150 people: -Refer to Potato Preferences table. What are the experimental units?

Which of the following graphics is the most important and most commonly used graphical presentation of quantitative data?

Kittens in Litters The following data represent the numbers of kittens born in litters for a particular breed of cat: 4, 5, 3, 6, 5, 5, 3, 4, 4, 5, 7, 5, 6, 6, 7, 4, 5, 5, 6, and 6. -Refer to the Kittens in Litters statement. What proportion of litters has fewer than five kittens?

Persons or objects on which an experiment is performed are called experimental units.

Friendly Encounter The Executive Board of a popular online dating website, called Friendly Encounter, wanted to know how to market the site by targeting the age groups most likely to be interested in its product. To find out, a random sample of 250 users was drawn from its database of participants who had been active during the previous month. The users were then categorized into age groups. The average frequency of access per week was recorded for each age group. The result was organized into the following table of data: -Refer to the Friendly Encounter table. What is the primary variable of interest in this experiment?

A politician who is running for office in a province with 3 million registered voters commissions a survey. In the survey, 5500 of the 10,000 registered voters interviewed say they plan to vote for her. Which of the following is the population of interest?

A bar chart for a categorical variable shows the same distribution of measurements in categories as the pie chart, except that the height of each bar measures how often a particular category was observed.

Tobacco Use A doctor is concerned that too many of her patients use tobacco. She conducted a survey of 200 randomly chosen patients; the results of her findings are shown below. -Refer to the Tobacco Use table. Determine the relative frequencies.

Suppose you have 180 observations divided into classes. One of the classes has a data class frequency of 36. Which of the following would be its relative class frequency?

The four classes: 0 to < 5, 5 to < 10, 10 to < 20, over 20, would be acceptable for developing a frequency distribution.

In constructing a pie chart for a categorical variable, one sector of the pie is assigned to each category of the variable.

Which of the following best describes the term "relative class frequency"?

What does the sum of the frequencies for all classes always equal?

A dotplot is a graphical portrayal of an absolute or relative frequency distribution of continuous quantitative data having the following characteristics: a. the lower and upper limits of the data classes are identified by tick marks on a horizontal axis, and b. the corresponding absolute or relative class frequencies are represented by the areas of contiguous rectangles that stand on top of each of these class intervals.

A pie chart is the familiar circular graph that shows how the measurements are distributed among the categories of a qualitative variable.

Bar charts can typically be formed with the bars vertical or horizontal without affecting the interpretation.

A continuous quantitative variable is one that may assume values at all points on an interval of values, with no gaps between possible values.

You asked ten of your classmates about their weight. On the basis of this information, you estimated that the average weight of all students at your school is 71.8 kilograms. What is this an example of?

A relative frequency distribution describes the proportion of the data values falling within each class, and may be presented in a histogram form.