Topic 3: Summary Statistics

A researcher compared the diastolic blood pressure readings for a group who had been undertaking meditation training with a control group.

The results are shown in the back-to-back histogram below.

Which statement is true?

• The control group’s data was bimodal and skewed.

• The control group’s data was bimodal and symmetrical.

• The meditation group’s data was bimodal and skewed.

• The meditation group’s data was unimodal and symmetrical.

The stem and leaf plot shows the number of shots needed to complete 25 games of pool on two tables.

Which is true?

 

• Both Tables have skewed data and have the same interquartile range.

• Table A has skewed data and has the same interquartile range as Table B.

• Table B has skewed data and has the same interquartile range as Table A.

• Table B has skewed data and has a greater interquartile range than Table A.

What is the interquartile range of the scores in the dot plot below?

• 3

• 6

• 6.5

• 7

Which of the following best describes the data displayed in the dot plot:

• Bimodal

   

• Negatively skewed

• Normally distributed

• Positively skewed

Two groups of participants in a trial, labelled A and B, were scored on a rating scale.

The results for the two groups are shown below.

Which statement is a correct description of the shape of the two distributions?

• Only Group A was bimodal and both groups were positively skewed.

   

• Only Group A was bimodal and only Group B was positively skewed

• Only Group B was bimodal and both groups were positively skewed

• Only Group B was bimodal and only Group A was positively skewed

Anna conducts a survey on the number of “friends” that people have on a social media site.

There were 160 people who took part in the survey.

The box-and-whisker plot below illustrates the results of the survey.

How many people had more than 40 “friends”?

 

• 40

• 75

• 95

• 120

Mei completed eight laps of an oval while training for football.

The times for each lap (to the nearest second) are shown below.

 

68, 55, 52, 48, 54, 54, 56, 65.

 

What was the mean and standard deviation of the times (correct to 1 decimal place).

Daisy analyses a set of data and produces the five number summary below.

                         9, 12, 21, 29, 31.

Which of the following is a correct statement about the data set?

• range = 22

  interquartile range = 17

• mean = 9

  range = 31

• median = 21

  interquartile range = 19.5

• mode = 29

  median = 9

A batter in a cricket team scores the following in one season:

 

                        {0, 0, 5, 21, 23, 24, 34, 36, 47, 49, 49}

The standard deviation of these scores is: (correct to one decimal place)

• 18.7

• 18.6

• 17.9

• 17.8

The mean, median and mode of a set of data, respectively, are:

• The average, middle number, most common number.  

• Most common number, average, middle number.

• Lowest number, middle number, highest number.

• The average, most common number, middle number.