Chapter 1 Stats

If we want to compare quantities of a categorical variable that are not part of a whole, we can use __________.

A bar graph

A professor collects information on students in her statistics course at Whatsamatta U. She records the students' blood type, age, sex, height, ethnicity and hours exercising in a typical week. In this context, "ethnicity" is _____________. (a) A categorical variable (b) A quantitative variable (c) Not a variable

A categorical variable

For very large data sets it is best to plot the data using ______. (a) A histogram (b) A stemplot (c) A dotplot (d) Either a stemplot or a dotplot

A histogram

A professor wants to determine the average age of all students enrolled in statistics courses at Whatsamatta U. She obtains data from 167 currently enrolled students. In this context, the variable of interest would be _________________. (a) A student (b) Age (c) The professor (d) Whatsamatta U. (e) None of these

Age

Members of a health club were asked which classes they took at the club (Zumba, Step, P90, etc.). What type of graph is best to display this data? (a) Pie chart (b) Bar chart (c) Stemplot (d) Histogram

Bar chart

300 people were asked the following question: How many times have you accessed the internet this week? - none - once or twice - three or four times - more than four times Which method of displaying the data could be used to display the data produced from that question? (a) Time Plot (b) Bar graph (c) Stemplot (d) Histogram

Bar graph

For research purposes, people were asked for the first 3 digits of their social security number (SSN). Would this variable be considered a categorical or quantitative variable? (a) Categorical (b) Quantitative (c) Neither

Categorical

A quantitative variable that can take any real numerical value within an interval is called a _______ variable.

Continuous

In statistics, the term "frequency" is used to refer to ______. (a) Percents (b) Counts (c) Differences (d) Averages

Counts

When performing exploratory data analysis, which of these should be done first? (a) Study the relationships among the variables (b) Examine each variable by itself. (c) Either examine each variable separately or study the relationships among variables. It does not matter which is done first as long as both are done.

Examine each variable by itself

True or False: When drawing a histogram, make sure to leave space between the bars so the graph will be easier to read.

False

True or False: When examining a data set, it is important to study the relationships between variables before examining each variable by itself.

False

When performing exploratory data analysis, which of these should be done first? (a) Graph the data. (b) Either graph the data or calculate numerical summaries. It does not matter which is done first as long as both are done. (c) Calculate numerical summaries of specific aspect of the data.

Graph the data

One of the reasons to use a time plot is to _________. (a) Help us visualize any cycles or trends in the data (b) Help us to see the distribution of a categorical variable (c) Help us to see the shape of the distribution of a quantitative variable (d) Help us determine outliers in the data

Help us visualize any cycles or trends in the data

Which type of plot is most commonly used to display the distribution of a single quantitative variable? (a) Bar graph (b) Pie chart (c) Histogram (d) Time plot

Histogram

A researcher is studying the eye color of mice. What type of variable is eye color in mice? (a) Discrete (b) Nominal (c) Continuous (d) Ordinal

Nominal

You collect data on the number of children that a random sample of adult women have. The distribution of children will be ____________. (a) Skewed to the left (b) Roughly symmetric (c) Skewed to the right (d) Uniform

Skewed to the right

Members of a health club were asked which classes they took at the club (Zumba, Step, P90, etc.). Why would it not be correct to display this data in a pie chart? (a) We don't have the actual data. (b) Not all the members take a class at the club so not all members would be clearly represented in the pie chart. (c) Some members may take more than one kind of class at the club, so those taking more than one class could create a potential percentage of more than 100. (d) We don't know all the classes that the club teaches, so these may be left off the pie chart.

Some members may take more than one kind of class at the club, so those taking more than one class could create a potential percentage of more than 100.

What can we say about the bars of a histogram? (a) Each bar represents a category of a categorical variable (b) The bars must be of equal height (c) The bars must have equal area (d) The bars should be of equal width

The bars should be of equal width

Which of the following is a true statement about histograms and bar graphs? (a) The horizontal axis of a bar graph is marked in the units of measurement of the variable, but the horizontal axis of a histogram identifies the items being compared, and may not have a unit of measurement. (b) The horizontal axes of histograms and bar graphs are always marked in the units of measurement of the variable (c) The horizontal axes of histograms and bar graphs identify the items being compared, and may not have a unit of measurement. (d) The horizontal axis of a histogram is marked in the units of measurement of the variable, but the horizontal axis of a bar graph identifies the items being compared, and may not have a unit of measurement.

The horizontal axis of a histogram is marked in the units of measurement of the variable, but the horizontal axis of a bar graph identifies the items being compared, and may not have a unit of measurement.

Participants in a research study are asked to rate their energy level using the responses 0 to 5, with "0" indicating "very low energy" and "5" indicating "very high energy". True or False: These responses are an example of an ordinal, categorical variable.

True

True or False: When examining a data set, begin by making graphs before moving on to numerical summaries.

True

When should you consider rounding the data before making a stemplot? (a) You should never round the data, since that would change the dataset. (b) When the data have many significant digits. (c) You should always round the data. (d) When you have a lot of leaves on just a few stems.

When the data have many significant digits

Students in an Introductory Statistics class were asked what month they were born in (January, February, etc.). Would it be correct to display this data in a pie chart? (a) No, some students may have been born in more than one month. (b) Yes, as we would have all the responses from the students. (c) Yes, as we can include all the categories that make up the whole and no individual will be counted more than once. (d) No, these would be quantities that are not part of the same whole.

Yes, as we can include all the categories that make up the whole and no individual will be counted more than once.