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CanadaON
Grade 7

13.02 Displaying data

Worksheet
Frequency tables
1

A gymnast received the following scores over 12 rounds of a competition:

Calculate the missing frequency to find how many times the gymnast scored 8.

Score56789
Frequency2111
2

Bill asks nine of his friends which pet they would like and writes down their responses below:

Dog, Fish, Cat, Cat, Fish, Dog, Fish, Fish, Dog

Construct a frequency table for these responses.

3

Brad stands at the school gate and tallies the hair colour of students as they enter the school. His results are shown in the table:

a

Construct a frequency table from Brad's tally.

b

Find the total number of students Brad tallied.

c

What percentage of students had red hair? Round your answer to two decimal places.

4

The following table shows the number of trains arriving either on time or late, at Union station during one week:

a

How many trains arrived on time on Thursday?

b

How many trains arrived late on Wednesday?

c

What percentage of the total trains arriving during the week, arrived on Friday? Round your answer to one decimal place.

d

What percentage of the trains arriving on Sunday were on time?

DayTrains on timeTrains arriving late
\text{Monday}146
\text{Tuesday}164
\text{Wednesday}182
\text{Thursday}155
\text{Friday}173
\text{Saturday}66
\text{Sunday}53
5

Fifteen airline passengers weigh their luggage. The weights in kilograms are listed below:

17, 20, 19, 19, 20, 21, 20, 22, 20, 19, 17, 16, 20, 20, 16

a

Construct a frequency table for this data.

b

How many passengers had luggage that weighed more than 20 kilograms?

c

The airline charges each passenger \$3 for every kilogram above 20\text{ kg}. Calculate the total charge for overweight luggage for this group of passengers.

6

A school nurse is investigating the number of sick days taken by students in a class, and constructs the following table:

a

Construct a frequency table for the number of sick days.

b

State the number of students who had no sick days.

c

State the most common number of sick days for the class.

StudentSick days
\text{Sally}0
\text{Lachlan}2
\text{Tara}1
\text{Xavier}4
\text{Luigi}2
\text{Nadia}4
\text{Lisa}0
\text{Dave}1
\text{Bill}3
\text{Danielle}4
7

Find the mode(s) of the following sets of scores:

a

12, 12, 13, 11, 13, 9, 13, 14, 9

b

14, 2, 5, 2, 2, 5, 5, 7, 12, 13, 13, 14

8

Explain how to find the mode(s) of the following set of scores.

Score212223242526
Frequency313739333834
9

Yvonne asks a number of her friends what their favourite colour is, and writes down their reponses below:

Blue, Pink, Blue, Yellow, Green, Pink, Pink, Yellow,

Green, Blue, Yellow, Pink, Yellow, Pink, Pink

a

Construct a frequency table.

b

How many friends did Yvonne survey?

c

Which colour is the mode?

10

Mrs Tran asks her students how many bedrooms they have in their house and writes their responses below:

3, 3, 4, 4, 3, 3, 4, 5, 2, 2, 4, 4

a

Complete the frequency table.

b

How many students did Mrs Tran survey?

c

State the modal number of bedrooms.

Number of BedroomsNumber of Students
1
2
3
4
5
11

Ms. Lee bought pizza for her class. She told her students they could eat as much as they wanted in two minutes. She counted up how many slices each student ate in that time and wrote her results below:

2, \, 2, \, 2, \, 3, \, 6, \, 0, \, 2, \, 3, \, 4, \, 2, \, 1, \, 1, \, 2, \, 2, \, 6

a

Complete the frequency table for this data.

b

How many students are in the class?

c

State the modal number of slices eaten.

Slices eatenNumber of Students
0
1
2
3
4
5
6
Grouped data
12

As part of a fuel watch initiative, the price of petrol at a service station was recorded each day for 30 days, and displayed in the frequency table:

a

What was the maximum price that could have occurred in the 30 day period?

b

Find the number of days where the price was above 139.9 cents.

Price (in cents per litre)Frequency
130.0- 134.94
135.0 - 139.99
140.0 - 144.912
145.0 - 149.95
13

The frequency table shows the resting heart rates of a number of people taking part in a study:

a

Find the number of people taking part in the study.

b

How many people had a resting heart rate between 40 and 59 beats/minute?

c

How many people had a resting heart rate of below 50 beats/minute?

Heart RateFrequency
30 - 3920
40 - 4922
50 - 5928
60 - 6937
14

A group of 30 people was surveyed about how many video games they had played in the past month. The results are shown in the given table:

a

Find the number of people who played 10 or more video games.

b

Find the number of people who played less than 5 games.

c

Find the number of people who played more than 4, but less than 15 video games.

d

State the modal class for the data.

\text{Number of video } \\\ \text{games played}\text{Frequency}
0 - 45
5 - 912
10 - 149
15 - 194
15

The heights of 200 selected rugby players were measured and results recorded in the following table:

a

If the average height of an Australian man is 175 \text{ cm}, find the percentage of rugby players that are shorter than average.

b

Find the percentage of rugby players with heights greater than 189 \text{ cm}.

Height (cm)Frequency
170 - 1748
175 - 17926
180 - 18461
185 - 18955
190 - 19441
195 - 1997
200 - 2042
16

The ages of golfers in a competition are listed below:

63, \, 69, \, 62, \, 61, \, 61, \, 68, \, 66, \, 63, \, 67, \, 66, \, 62, \, 66, \, 61, \,\\\\ 69, \, 59, \, 63, \, 69, \, 63, \, 57, \, 60, \, 57, \, 67, \, 59, \, 62, \, 62, \, 57

Complete the frequency table for this data.

AgeFrequency
57-61
62-66
67-71
\text{Total}
17

A tree farmer measured the height of newly planted saplings to the nearest centimetre. The results are shown below:

16, \, 17, \, 27, \, 36, \, 16, \, 27, \, 22, \, 37, \, 17, \, 17, \\\\ 26, \, 22, \, 37, \, 27, \, 22, \, 21, \, 26, \, 27, \, 37, \, 31, \\\\ 27, \, 37, \, 27, \, 21, \, 22, \, 32, \, 32, \, 36, \, 17, \, 32, \\\\ 31, \, 37, \, 27, \, 26, \, 37, \, 32, \, 36, \, 27, \, 26

a

Complete the frequency table.

b

State the range.

c

Find the number of saplings that were measured.

d

In which height interval does the mode lie?

e

Find the number of saplings that have a height lower than 25 cm.

Height (cm)Frequency
15-19
20-24
25-29
30-34
35-39
18

A group of high school students wanted to convince their principal that the school needed airconditioning. They measured the temperature (in \degree \text{C}) in a classroom at 1 pm every day during February and recorded the following results:

35, \, 26, \, 32, \, 29, \, 29, \, 32, \, 26, \, 29, \, 35, \, 23, \, 23, \, 32, \, 35, \, 26, \\\\ 26, \, 23, \, 26, \, 29, \, 32, \, 35, \, 23, \, 26, \, 29, \, 29, \, 29, \, 32, \, 23, \, 29

a

Complete the frequency table.

b

Which temperature group is the highest recorded temperature?

c

How many days in February had a temperature higher than 30\degree \text{C}?

d

Hence calculate the number of days that had a temperature lower than or equal to 30\degree \text{C}.

\text{Temperature in}\degree \text{C}\text{Frequency}
22-24
25-27
28-30
31-33
34-36
19

Neil tracks how many views his website receives each week for ten weeks. The results are given in the following table:

\text{Week }12345678910
\text{Views }601612618620636643644659670691

Construct a frequency table for this data set by grouping the data into sets of twenty, with the first group being 600-619.

20

Consider the data below:

48, \, 31, \, 85, \, 46, \, 56, \, 33, \, 66, \, 48, \, 86, \, 74, \, 64, \, 63, \, 50, \\\\ 52, \, 62, \, 67, \, 33, \, 66, \, 81, \, 40, \, 58, \, 63, \, 68, \, 58, \, 78

Construct a frequency table for this data by grouping the data into sets of ten, with the first group being 30-39.

21

A PE teacher asked her students to do as many push-ups as they could, and recorded the number of push-ups each student completed below:

38, \, 31, \, 12, \, 14, \, 29, \, 7, \, 21, \, 19, \, 46, \, 13, \, 23, \, 3, \, 13, \, 17, \, 4, \, 6, \, 11, \, 24, \, 5, \, 20

a

Construct a frequency table for this data set by grouping data into sets of ten, with the first group being 0-9.

b

Find the number of students in the class.

c

What percentage of students could perform at least 30 pushups?

d

What percentage of students could not perform at least 40 pushups?

Line plots
22

A group of people were surveyed on the number of websites they visit on a daily basis. The results are displayed in the given line plot:

Complete the frequency table based on the line plot:

Number of websites visited dailyFrequency
0
1
2
3
4
5
6
23

The given line plot shows the number of students in each section of the school band:

a

Which section has the least members?

b

Find the number of people in the band.

c

How many more people are there in the Strings section than in the Brass section?

24

Each judge on a cooking show gives contestants a rating between 1 and 5. The line plot shows the scores given to the winning contestant:

a

How many judges gave the contestant a rating of 4?

b

How many judges gave the contestant a rating of 4 or more?

c

How many judges gave the contestant a rating of 2 or less?

25

The goals scored by a soccer team in a single season are represented in the line plot:

a

State the most common number of goals scored.

b

Find the middle number of goals scored.

26

A group of concert attendees are asked: "How old are you?". The responses were:

22, \, 17, \, 17, \, 17, \, 19, \, 21, \, 17, \, 22, \, 21, \, 18, \, 18, \, 17, \, 18, \, 22, \, 18
a

Plot the responses on a line plot.

b

How many people were 19 or older?

27

In a study, a group of people were shown 30 names, and after one minute they were asked to list the names they could remember. The results are presented in the line plot:

a

How many people took part in the study?

b

What is the highest number of names someone remembered?

c

What was the lowest number of names someone remembered?

28

Aviation glass is manufactured to be 12\text{ mm} thick. If the glass is too thin (less than 11.5\text{ mm}) or too thick (more than 12.5\text{ mm}) the aircraft will fail its glass safety check.

A regional airport conducts a glass safety check of all aircraft landing on their runways over a one month period and displays the results in the line plot below:

a

How many aircraft were checked for glass safety?

b

State the lowest level of glass thickness measured.

c

State the most common glass thickness measured.

d

What percentage of aircrafts failed the glass safety check?

29

A supermarket manager takes a note every time an employee is late to work, and how late they were (rounded to the nearest half hour). The dot plot below shows their results for the last month:

If an employee is more than 1 hour late, the manager fines them \$10. How much money did the manager collect in fines over the last month? Explain your answer.

30

The following line plots display how many seconds it took for students to race from their classroom to their locker:

a

State the slowest time recorded.

b

Which teacher's class had the largest range of times?

c

Which teacher's class had the fastest student?

31

In each game of the season, a basketball team recorded the number of 'three-point shots' they scored. The results for the season are represented in the following line plot:

a

How many games were played during the season?

b

If the team scored 4 three-point shots in a game, how many points are scored from three-point shots?

c

What was the total number of points scored from three-point shots during the season?

Stem-and-leaf plots
32

This stem-and-leaf plot records the ages of customers at a beachside cafe last Sunday. Use the stem-and-leaf plot to complete the following frequency table:

Leaf
11\ 5\ 9
22\ 3\ 5\ 6\ 7\ 9
30\ 1\ 2\ 4\ 6\ 7
41\ 3\ 4\ 6\ 8\ 9
51\ 4\ 7
62\ 4\ 5\ 6\ 7

Key: 5\vert 2 = 52

AgeFrequency
10-19
20-29
30-39
40-49
50-59
60-69
33

An online booking service allows customers to book tickets to see performers in concert. Over the last month the service has been tracking how many tickets are sold in the first five seconds after they become available, and their results are displayed in the given stem-and-leaf plot:

a

How many concert events does this data set represent?

b

Find the highest number of tickets sold in the first five seconds.

c

Find the difference between the highest and lowest number of tickets sold in the first five seconds.

Leaf
10\ 0\ 1\ 2\ 2\ 3\ 4\ 8
20\ 1\ 5\ 7\ 8\ 9
30\ 2\ 6\ 8
4
56

Key: 1\vert 2 = 12 tickets sold

34

The following stem and leaf plot shows the age of people who enter through the gates of a theme park in the first ten minutes:

a

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

b

State the age of the youngest person.

c

State the age of the oldest person.

d

Find the age difference between the youngest and oldest person.

Leaf
11\ 2\ 3\ 3\ 4\ 4\ 6\ 6\ 7
20\ 2\ 4\ 9\ 9
32\ 5\ 5\ 5
4
53

Key: 1\vert 2 = 12 years old

35

A city council selected a number of houses at random. They determined the fastest travel time (in minutes) from each house to the nearest hospital, and recorded the following results:25, \, 37, \, 16, \, 27, \, 27, \, 35, \, 21, \, 18, \, 19, \, 49, \, 14, \, 19, \, 31, \, 42, \, 18

Represent this data as an ordered stem-and-leaf plot.

36

The level of mercury in 40 different water samples was tested and recorded in the following stem-and-leaf plot:

a

State the highest reading.

b

Find the 8th lowest reading.

c

How many readings of 100 or higher were recorded?

d

The level of mercury is deemed to be safe if the reading is 103 or lower. What percentage of the readings are safe?

Leaf
93\ 3\ 3\ 3\ 6\ 7\ 8\ 8\ 9\ 9
100\ 0\ 3\ 3\ 4\ 4\ 5\ 5\ 6\ 7\ 9
112\ 3\ 4\ 4\ 5\ 6\ 8\ 9\ 9
120\ 1\ 1\ 1\ 2\ 2\ 3\ 5\ 6\ 7

Key: 1\vert 2 = 12 units

37

The given stem-and-leaf plot shows the ages of 20 employees in a company:

a

Find the number of employees in their 30s.

b

State the age of the oldest employee.

c

State the age of the youngest employee.

Leaf
20\ 1\ 1\ 2\ 8\ 8\ 9
30\ 2\ 4\ 8\ 8
41\ 1\ 1\ 2\ 5
53\ 4\ 8

Key: 1\vert 2 = 12 years old

38

A cyclist measured his heart rate immediately after finishing each event in which he competed. The results are recorded in the following stem and leaf plot:

a

Calculate the difference between his slowest and fastest heart rate.

b

For each extra heartbeat per minute, it takes 7 seconds longer for him to recover. How much longer would it take to recover when he finishes with the fastest heart rate, compared to when he finishes with the slowest heart rate?

Leaf
161\ 4\ 4\ 4\ 6\ 8\ 8
170\ 0\ 4\ 6\ 8
180\ 2\ 3\ 3
191\ 2\ 3\ 4\ 7\ 7\ 8

Key: 1\vert 2 = 12 beats per minute

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Outcomes

7.D1.1

Explain why percentages are used to represent the distribution of a variable for a population or sample in large sets of data, and provide examples.

7.D1.2

Collect qualitative data and discrete and continuous quantitative data to answer questions of interest, and organize the sets of data as appropriate, including using percentages.

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