Exam 1: Describing Data With Graphs

Relative frequency distributions are specifically constructed for analyzing discrete data.

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 are the experimental units?

Individual observations within each class may be found in a frequency distribution.

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. Construct a relative frequency bar chart.

Absenteeism A high school band teacher has a record of each student's absence. The results, in days, are 3, 4, 7, 2, 2, 1, 0, 0, 1, 0, 3, 3, 2, 1, 6, 0, 1, 0, 1, 1, 1, 5, 3, 1, 1, 0, 0, 2, 1, 2, 1, 0, 0, and 4. -Refer to the Absenteeism statement. Summarize the data using frequencies and relative frequencies.

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. From this sample data, what may the Executive Board deduce about the approximate percentage of its dating site users being under 40 years of age?

Absenteeism A high school band teacher has a record of each student's absence. The results, in days, are 3, 4, 7, 2, 2, 1, 0, 0, 1, 0, 3, 3, 2, 1, 6, 0, 1, 0, 1, 1, 1, 5, 3, 1, 1, 0, 0, 2, 1, 2, 1, 0, 0, and 4. -Refer to the Absenteeism statement. What proportion of students has been absent less than three days?

In a line chart, the horizontal axis represents time (such as months, years), and the vertical axis represents the value of the variable of interest.

A branch of the statistics discipline that is used to develop and utilize techniques for effectively presenting numerical information is called inferential statistics.

Social Media The Executive Board of a popular social media website wanted to know which kinds of professional people were accessing their website regularly over a two-month period. To that end, a random sample from its database of active users was collected. The following data were recorded: -Refer to the Social Media table. Name two of the most common graphical techniques which may be used by the Executive to show to their staff the results of their experiment.

Which is the best type of chart for comparing two sets of qualitative data?

Relative frequency histograms are used most often to display bivariate data.

Weight of Bag of Potatoes The weight of a bag of potatoes is supposed to be 5 kilograms. Each bag may vary slightly from this standard. The weights for 18 bags of potatoes are as follow: 4.5, 5.0, 5.1, 6.0, 5.2, 3.9, 4.7, 4.9, 5.5, 5.6, 5.1, 4.9, 6.1, 4.8, 4.9, 5.1, 4.6, and 3.5. -Refer to the Weight of Bag of Potatoes statement. Construct a stem-and-leaf plot to describe the data.

Groupings of data created to enhance an understanding of them, usually by making the groups collectively exhaustive and mutually exclusive, are called classes or categories.

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 the Potato Preferences table. What is the variable being measured? Is it qualitative or quantitative?

When a distribution has more values to the right and tails to the left, then it is considered to be skewed to the right.

A market share of 78.5% can be represented in a pie chart by a slice having a central angle measured in degrees. In this case, what would be the size of the central angle of the market share?

A high school volleyball coach has summarized the wins, losses, and ties of her team for the past four years in the following stacked bar chart. Interpret the chart.

The data values plotted on a line graph are connected by drawing a straight line between each pair of successive points.

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 the Potato Preferences table. What proportion of people prefer french fries or steak fries?