Practise identifying variables in study contexts, classifying categorical and quantitative data, and distinguishing discrete counts from continuous measurements.
An environmental research agency conducted a study of a certain state's roadsides to estimate the mean number
of discarded cans and bottles per mile of public road. The state's public roads were grouped into three types:
Major highways: major paved roads designed for high traffic volume
Minor highways: smaller paved roads designed for low traffic volume
Unpaved roads: gravel and dirt roads
There are about 100,000 miles of public roads in the state. The environmental research agency defined a
sampling unit to be a one-mile segment of public road. Using a database supplied by the state's department of
transportation, the agency randomly selected 30 one-mile road segments for each of the three types of roads.
Researchers from the agency searched the roadsides along each of the selected one-mile road segments and
recorded the number of discarded cans and bottles. Results are shown in the table below.
What is the variable of interest in the study?
What is the parameter of interest?
A trainer has two weight lifting classes, Class I and Class II. Each class has 9 amateur adult males and 1 professional adult male. Their body weights and number of bench press reps with 225 pounds are shown in the following dotplots. The professionals are designated as A and B.
Identify and classify the quantitative variables.
A delivery company keeps track of truckloads with two variables: number of parcels and total weight. Are these variables discrete or continuous?
Both are discrete.
Both are continuous.
Number of parcels is discrete, and weight is continuous.
Number of parcels is continuous, and weight is discrete.