MIDTERM PRACTICE EXAM B

Front

What is a categorical variable?

Back

A categorical variable is a type of variable that can take on one of a limited, and usually fixed, number of possible values, assigning each individual or other unit of observation to a particular group or nominal category on the basis of some qualitative property.

Front

What is a quantitative variable?

Back

A quantitative variable is a type of variable that can be measured and expressed numerically, allowing for mathematical operations to be performed on the values.

Front

What is the mean in statistics?

Back

The mean is the average of a set of numbers, calculated by adding all the values together and dividing by the number of values.

Front

What is standard deviation?

Back

Standard deviation is a measure of the amount of variation or dispersion in a set of values, indicating how much individual data points differ from the mean.

Front

What does a correlation coefficient of r = -0.05 indicate?

Back

A correlation coefficient of r = -0.05 indicates a very weak negative linear relationship between two variables.

Front

What is a least-squares regression line?

Back

A least-squares regression line is a straight line that best fits the data points in a scatter plot, minimizing the sum of the squares of the vertical distances of the points from the line.

Front

What is an interquartile range (IQR)?

Back

The interquartile range (IQR) is a measure of statistical dispersion, calculated as the difference between the third quartile (Q3) and the first quartile (Q1) of a data set.

Front

How do you calculate the interquartile range?

Back

To calculate the interquartile range, first find Q1 (the median of the lower half of the data) and Q3 (the median of the upper half of the data), then subtract Q1 from Q3: IQR = Q3 - Q1.

Front

What is a stem-and-leaf plot?

Back

A stem-and-leaf plot is a method of displaying quantitative data in a graphical format, similar to a histogram, that helps to visualize the shape of a distribution.

Front

What is the difference between a median and a mean?

Back

The median is the middle value of a data set when arranged in order, while the mean is the average of all values in the data set.