Topics
6. Bivariate Scatterplots
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AustraliaWA
Year 12

6.03 Line of best fit

Lesson
Worksheet
Practice
Worksheet
Line of best fit
1

Draw an approximate line of best fit by hand for each of the the scatter plots below:

a
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y
b
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c
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d
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e
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f
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g
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h
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i
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2

The following scatter plot displays data for the number of people in a room and the room temperature, as collected by a researcher:

Draw an approximate line of best fit by hand for the scatter plot.

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\text{Number of people}
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\text{Temperature} \left(\degree \text{C} \right)
3

The following scatter plot displays data for the number of copies of a particular book sold at various prices:

Draw an approximate line of best fit by hand for the scatter plot.

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\text{Price}
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\text{Copies sold}
Applications
4

The average monthly temperature and the average wind speed, in knots, in a particular location was plotted over several months. The graph shows the points for each month’s data and their line of best fit:

Use the line of best fit to approximate the wind speed on a day when the temperature is 5\degree \text{C}.

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\text{Temperature}(\degree \text{C})
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\text{Speed}
5

The following scatter plot shows the data for two variables, x and y:

a

Sketch the line of best fit for this data.

b

Use your line of best fit to estimate the value of y when:

i

x = 4.5

ii

x = 9

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y
6

The following scatter plot graphs data for the number of ice blocks sold at a shop on days with different temperatures.

a

Sketch the line of best fit for this data.

b

Use your answer line of best fit to estimate the number of ice blocks that will be sold on a:

i

31 \degree \text{C} day

ii

42 \degree \text{C} day

c

Does the number of ice blocks sold increase or decrease as the temperature increases?

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\text{Temperature}(\degree \text{C})
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\text{Ice blocks}
7

The following scatter plot graphs data for the number of balls hit and the number of runs scored by a batsman:

a

Sketch the line of best fit for this data.

b

Use the line of best fit to estimate the number of runs scored by the batsman after hitting:

i

27 balls

ii

66 balls

c

Is the relationship between the two variables positive or negative?

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\text{Balls Hit}
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\text{Runs}
8

The following scatter plot graphs data for the number of copies of a particular book sold at various prices.

a

Sketch the line of best fit for this data.

b

Use the line of best fit to find the number of books that will be sold when the price is:

i

\$33

ii

\$18

c

Is the relationship between the two variables positive or negative?

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\text{Price}
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\text{Copies}
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Outcomes

3.4.15

fit a trend line by eye

3.4.16

interpret relationships in terms of the variables, for example, describe trend as increasing or decreasing

3.4.17

use the trend line to make predictions, both by interpolation and extrapolation

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