STAT 210 Quizzes 5-8

When describing a distribution, which of the following things must you describe?

Center, spread, shape and unusual features

What type of characteristic is "number of enrolled students in a class"?

Discrete quantitative variable

True or false: a stem-and-leaf plot and a histogram are graphical methods for displaying qualitative data.

False

Which of the following is a measure of center that would be heavily influenced by outliers?

Mean

Suppose the shape of a stem and leaf plot is skewed right. What is the best measure to describe the center?

Median

Which of the following is a measure of center that is resistant to outliers?

Median

A random sample of 85 graduate level classes was selected and the number of enrolled students during the Fall 2017 semester was recorded for each. The data is displayed in the boxplot below. Use this boxplot to completely describe the center of the distribution of the number of enrolled students in this sample of 85 graduate level classes.

Median= 17.5

When describing a distribution, which of the following do you not use?

Size

A random sample of 85 graduate level classes was selected and the number of enrolled students during the Fall 2017 semester was recorded for each. The data is displayed in the boxplot below. Use this boxplot to describe the shape of the distribution of the number of enrolled students in this sample of 85 graduate level classes.

Skewed Left

When income/salaries of a collection of people are graphed the distribution usually has a very long tail to the right because there are a few people who make LOTS of money while most others earn much less. What type of distribution does this describe?

Skewed right

Which of the following is a measure of spread that is influenced by outliers?

Standard deviation

Which of the following is a correct statement?

The IQR is a measure of spread around the median.

A simple random sample of 16 classes being taught at VCU during the fall 2017 semester was selected and for each the number of enrolled students recorded. The data is given below. 63 26 47 48 12 72 52 31 55 126 66 35 22 44 32 37 Calculate the range of the data.

114

A simple random sample of 16 classes being taught at VCU during the fall 2017 semester was selected and for each the number of enrolled students recorded. The data is given below. 63 26 47 48 12 72 52 31 55 126 66 35 22 44 32 37 Calculate the standard deviation of the data.

26.56

A simple random sample of 16 classes being taught at VCU during the fall 2017 semester was selected and for each the number of enrolled students recorded. The data is given below. 63 26 47 48 12 72 52 31 55 126 66 35 22 44 32 37 Calculate the Interquartile Range of the data.

27.5

A simple random sample of 16 classes being taught at VCU during the fall 2017 semester was selected and for each the number of enrolled students recorded. The data is given below. 63 26 47 48 12 72 52 31 55 126 66 35 22 44 32 37 Calculate the median of the data.

45.5

A simple random sample of 16 classes being taught at VCU during the fall 2017 semester was selected and for each the number of enrolled students recorded. The data is given below. 63 26 47 48 12 72 52 31 55 126 66 35 22 44 32 37 Calculate the mean of the data.

48

Suppose the shape of a stem and leaf plot is skewed right. What is the best measure to describe the spread?

Interquartile Range

Which of the following is a measure of spread that is resistant to outliers?

Interquartile range

Which of the following statistics is a measure of spread that would be resistant to outliers?

Interquartile range