Scatter plots

Name:

Date:

Class:

Quick Questions

Shade in the A or B circle for each question.

1. A scatter plot shows hours of sleep (x) and test score (y) for 30 students. How many dots does it show?

A 30 dots, one for each student

B 1 dot showing the average of all students

2. Which data suits a scatter plot?

A Height and shoe size of each student in a class

B Favourite pizza topping of each student in a class

3. You want to see if more study time goes with higher marks. Which choice of fields is better?

A x = study hours, y = marks

B x = student name, y = marks

4. The dots form a cloud that climbs from the bottom left to the top right. What does this suggest?

A As x goes up, y tends to go down

B As x goes up, y tends to go up too

5. The dots are spread all over the chart with no clear shape. What does this suggest?

A There is a very strong relationship between x and y

B There is little or no relationship between x and y

Match the Pairs

Draw a line connecting each item on the left to its match on the right.

Left column		Right column
1x = Hours of sleep, y = Test score		AAn outlier: a record that does not fit the pattern of the other dots
2A dot far away from the cloud		BA far-away dot is an outlier. Check whether it is a data error or a real unusual result before removing it.
3A cloud of dots sloping upward from bottom left to top right shows that as x goes up, y tends to go up		Cx = Age (years), y = Height (cm)
4A scatter plot needs two numeric fields, one for the x axis and one for the y axis		DFavourite colour is text, not a number. A scatter plot needs two numeric fields, so use a numeric field such as Hours of practice as x.
5Scatter plot with x = Favourite colour, y = Score		EStudy time vs marks: dots rise to the right
6One dot sits far from the rest, so delete it and ignore it		FEach student is one dot, placed by their sleep hours across and their test score up

Definitions

scatter plot

Fill in the Blanks

Complete each line of code by filling in the missing parts.

Chart type: _______ plot (one dot per record)

x: Hours of study _: Test score

Both x and y must be _______ fields

A dot far from the cloud is an _______

Dots rise left to right: ________ link

Spot the Error

Shade in the letter of the line that contains an error.

Question 1

A Chart: scatter plot

B x = Student name

C y = Test score

D Each row makes one dot

Question 2

A Chart: scatter plot

B x = Age of car (years)

C y = Car colour

D Each row makes one dot

Question 3

A Dots slope up to the right

B This shows a negative link

C More study, higher scores

Question 4

A Dots slope up to the right

B This shows a negative link

C As x rises, y falls

Question 5

A Most dots form a tight cloud

B One dot is far from the rest

C That dot is an outlier

D Delete it without checking

Answer Key

Scatter plots

Section A: Quick Questions

A — 30 dots, one for each student

A — Height and shoe size of each student in a class

A — x = study hours, y = marks

B — As x goes up, y tends to go up too

B — There is little or no relationship between x and y

Section B: Match the Pairs

x = Hours of sleep, y = Test score → Each student is one dot, placed by their sleep hours across and their test score up

A dot far away from the cloud → An outlier: a record that does not fit the pattern of the other dots

A cloud of dots sloping upward from bottom left to top right shows that as x goes up, y tends to go up → Study time vs marks: dots rise to the right

A scatter plot needs two numeric fields, one for the x axis and one for the y axis → x = Age (years), y = Height (cm)

Scatter plot with x = Favourite colour, y = Score → Favourite colour is text, not a number. A scatter plot needs two numeric fields, so use a numeric field such as Hours of practice as x.

One dot sits far from the rest, so delete it and ignore it → A far-away dot is an outlier. Check whether it is a data error or a real unusual result before removing it.

Section C: Definitions

scatter plot — A chart with one dot per record, using two numeric fields as x and y. The cloud of dots shows if the variables are related, and a dot far from the rest is an outlier.

Section D: Fill in the Blanks

Chart type: scatter plot (one dot per record)

x: Hours of study
y: Test score

Both x and y must be numeric fields

A dot far from the cloud is an outlier

Dots rise left to right: positive link

Section E: Spot the Error

B — A scatter plot needs a numeric field on the x axis. Student name is text, so it should be a number such as x = Hours studied.

C — The y field must also be numeric. Car colour is text, so the line should be y = Price ($).

B — Dots that slope up to the right show a positive link: as x rises, y rises. It should say positive, not negative.

A — A negative link, where y falls as x rises, shows as dots sloping down to the right. Sloping up would be a positive link.

D — An outlier should be checked first. It might be a typing mistake or a real unusual value. It should not be deleted without checking.