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8.04 Dot plots and stem plots

Worksheet
Dot plots
1

For a dot plot, describe how we determine the frequency of each score.

2

The goals scored by a football team in their matches are represented in the given dot plot:

Construct a frequency table for this data.

3

Consider the following dot plot showing students' scores:

a

Construct a frequency table for this data.

b

How many students scored above 20?

c

How many students scored below 30?

4

Construct a dot plot that represents the following data:

49,\, 49,\, 49,\, 51,\, 48,\, 47,\, 50,\, 49,\, 51,\, 50,\, 51,\, 49,\, 52,\, 47,\, 50,\, 49

51,\, 48,\, 51,\, 51,\, 50,\, 48,\, 49,\, 52,\, 49,\, 47,\, 47,\, 52,\, 52,\, 49,\, 47,\, 48

52,\, 48,\, 51,\, 51,\, 49,\, 52,\, 48,\, 48,\, 52,\, 50,\, 48,\, 47,\, 52,\, 52,\, 52,\, 48

5

A teacher made the following dot plot to display the number of boys and girls in the class:

a

How many girls are there in the class?

b

How many more girls are there compared to boys?

c

How many students are there in the class altogether?

d

What percentage of the class are girls? Round your answer to one decimal place.

6

A teacher made the following dot plot to display the number of cats and dogs owned by students in the class:

a

How many cats are owned by students?

b

How many more cats are there than dogs?

c

How many pets are there altogether?

d

What fraction of the pets are cats?

7

The number of goals scored in each of Bob’s soccer games is shown on the following dot plot:

a

How many times were five goals scored?

b

State the number of goals that were scored most often.

c

State the number of goals that were scored least often.

d

How many games were played in total?

8

A survey was conducted and the hair colours of the participants were recorded in the following dot plot:

a

Which hair colour is most common?

b

Which hair colour is least common?

c

How many more people had grey hair than black hair?

d

How many people were surveyed in total?

9

Mr. Wong counted the different eye colours of his students in his karate class. He recorded them in the following dot plot:

a

Which eye colour is most common?

b

Which eye colour is least common?

c

How many more people have brown eyes than olive eyes?

10

A single die was rolled several times. The outcomes were recorded in the following dot plot:

a

Which outcome occurred most frequently?

b

Which outcome was least frequent?

c

How many times was the die rolled in total?

11

Each student in the class was asked to write down the number of siblings they had. The teacher recorded the results in the following dot plot:

a

How many siblings do most students have?

b

Which number of siblings is the least frequent?

c

How many more students had 4 siblings than 1 sibling?

12

The following dot plot shows the numbers of different pets in a pet shop:

a

What is the total number of pets in the shop?

b

Which type of pet is the least?

c

How many more turtles are there than cats?

13

Mrs. Lee took a survey of the type of pets owned by her students:

a

Which type of pet is most common?

b

Which type of pet is the least common?

c

How many students have a rabbit?

d

State whether each of the following pets could belong to the Other category:

i

Birds

ii

Cats

iii

Mice

iv

Dogs

14

Christa is a casual nurse. She used a dot plot to keep track of the number of shifts she did each week for a number of weeks.

a

In this dot plot, what does each dot represent?

b

What was the most frequently occurring number of shifts per week?

c

Over how many weeks did Christa record her shifts?

d

For how many weeks did she work 5 shifts?

e

How many weeks did she work less than 6 shifts?

f

If Christa works at least 6 shifts a week, she buys a weekly train ticket. What proportion of the time did she buy a weekly train ticket?

Stem-and-leaf plots
15

State whether the following sentences are true or false in regards to an ordered stem-and-leaf plot:

a

The scores are ordered.

b

A stem-and-leaf plot does not give an idea of outliers and clusters.

c

It is only appropriate for data where scores have high frequencies.

d

The individual scores can be read on a stem-and-leaf plot.

16

Create a frequency table for the data in the following stem-and-leaf plot:

Leaf
11\ 2\ 3\ 7
23\ 4\ 7\ 7\ 7\ 9
32\ 7\ 9
40\ 1\ 1\ 5\ 6
52\ 6

Key: 1 \vert 2 = 12

17

Create a stem-and-leaf plot for the following data set:

24,\, 26,\, 25,\, 37,\, 36,\, 37,\, 37,\, 38,\, 41,\, 46,\, 49,\, 56,\, 67,\, 63,\, 67,\, 68,\, 69,\, 75,\, 80,\, 80

18

The scores, out of 100, for a recent spelling test are shown in the following stem plot:

a

How many students took the test?

b

What was the highest score on the test?

c

What test score occurred the most frequently?

d

How many marks separate the highest score and the most frequent score?

Leaf
62\ 3\ 3\ 6\ 6\ 7
70\ 1\ 1\ 1\ 1\ 4\ 5\ 8
81\ 1\ 2\ 3\ 4\ 5\ 6\ 9\ 9\ 9
94\ 5\ 7\ 9

Key: 1 \vert 2 = 12

19

The stem-and-leaf plot below shows the age of people to enter through the gates of a concert in the first 5 minutes:

a

How many people passed through the gates in the first 5 minutes?

b

What was the age of the youngest person?

c

What was the age of the oldest person?

d

How many people who enter through the gates were under 25 years old?

e

What proportion of the concert-goers were under 25 years old?

Leaf
12\ 4\ 5\ 6\ 6\ 9\ 9
21\ 2\ 6\ 7\ 8\ 9\ 9
31\ 3\ 8\ 8
4
55

Key: 1|2=12

20

The level of mercury in 40 fishing waters was tested and recorded. The results are given in the following stem-and-leaf plot:

a

What was the second highest reading?

b

In how many places was a reading of 117 or higher recorded?

c

What was the 11th lowest score?

d

If the safe level of mercury is recommended to be 109 or lower

i

How many fishing waters have safe levels of mercury?

ii

What percentage of the places have safe levels of mercury?

Leaf
91\ 3\ 5\ 5\ 6
101\ 2\ 4\ 4\ 5\ 5\ 6\ 8\ 9\ 9
111\ 1\ 2\ 3\ 3\ 3\ 5\ 6\ 7\ 7\ 7\ 8\ 8\ 8\ 8\ 9
122\ 2\ 2\ 2\ 2\ 3\ 4\ 6\ 9

Key: 1|2=12

21

A cyclist measured his heart rate immediately after finishing each event in which he competed. The results are recorded in a stem-and-leaf plot, but two values are missing:

a

He can remember no number appears twice in the plot. What is the smaller missing number?

b

If both missing numbers sum to 367, what is the second number?

Key: 12|3 = 123

22

The size of each earthquake that occurred over a three year period, measured from 0 to 9.9, is recorded in a stem-and-leaf plot:

a

What was the size of the largest earthquake measured?

b

An earthquake of size 6 or greater causes significant damage to buildings. How many of the earthquakes caused significant damage to buildings?

c

Students are asked to randomly choose an earthquake to report on. What is the probability that the first person picks an earthquake that measured between 8 and 9 (inclusive)?

Leaf
09
11\ 5
21\ 2\ 2\ 3\ 3\ 5\ 6\ 6\ 6\ 7\ 9\ 9
30\ 2\ 8
40\ 6\ 6\ 8\ 8\ 9
55\ 7\ 7\ 8
60\ 2\ 4\ 4\ 9
71\ 5\ 7
80\ 4\ 5\ 8

Key: 4|6=4.6

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Outcomes

ACMEM046

display numerical data as frequency distributions, dot plots, stem and leaf plots, and histograms

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