Exam 2: Describing the Distribution of a Variable

The value of the mean times the number of observations equals the sum of all of the data values.

The only meaningful way to summarize categorical data is with counts of observations in the categories.

The median can also be described as the

The median of a data set with 30 values would be the average of the 15^th and the 16^th values when the data values are arranged in ascending order.

Which of the states listed paid their teachers average salaries that are below 75% of all average salaries?

Unlike histograms,box plots depict only one aspect of a variable.

Researchers are conducting a review of the "war against poverty" in the latter half of the twentieth century.As part of their analysis,the proportion of Americans under the age of 18 who lived below the poverty line for each of the years 1959 through 2000 is used to generate the following time series plot. ​ How successful was the United States in its efforts to win "the war against poverty" during the 90's?

A variable (or field or attribute)is a characteristic of members of a population,whereas an observation (or case or record)is a list of all variable values for a single member of a population.

Abby has been keeping track of what she spends to stream movies.The last seven week's expenditures,in dollars,were 6,4,8,9,6,12,and 4.The mean amount Abby spent streaming movies over these 7 weeks is $7.

Two common ways of displaying categorical data is column charts and pie charts.

The number of car insurance policy holders is an example of a discrete numerical variable.

The core purpose of time series graphs is to detect historical patterns in the data.

The mode is best described as the

In a box plot,the asterisk inside the box indicates the location of the

Which measure of variability is defined as the maximum value of a data set minus the minimum value of a data set?

Data that arise from counts are best described as _____ data.

Expressed in percentiles,the interquartile range is the difference between the _____ percentiles.

In order for the characteristics of a sample to be generalized to the entire population,the sample should be _____ the population.

Both ordinal and nominal variables are categorical.

The mean is a measure of central tendency.