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Date May 2017 Marks available 1 Reference code 17M.2.SL.TZ2.S_2
Level Standard Level Paper Paper 2 Time zone Time zone 2
Command term Write down Question number S_2 Adapted from N/A

Question

The maximum temperature T , in degrees Celsius, in a park on six randomly selected days is shown in the following table. The table also shows the number of visitors, N , to the park on each of those six days.

M17/5/MATME/SP2/ENG/TZ2/02

The relationship between the variables can be modelled by the regression equation N = a T + b .

Find the value of a and of b .

[3]
a.i.

Write down the value of  r .

[1]
a.ii.

Use the regression equation to estimate the number of visitors on a day when the maximum temperature is 15 °C.

[3]
b.

Markscheme

evidence of set up     (M1)

eg correct value for a or b

0.667315, 22.2117

a = 0.667 ,   b = 22.2     A1A1     N3

[3 marks]

a.i.

0.922958

r = 0.923     A1     N1

[1 marks]

a.ii.

valid approach     (M1)

eg 0.667 ( 15 ) + 22.2 ,   N ( 15 )

32.2214     (A1)

32 (visitors) (must be an integer)     A1     N2

[3 marks]

b.

Examiners report

[N/A]
a.i.
[N/A]
a.ii.
[N/A]
b.

Syllabus sections

Topic 4—Statistics and probability » SL 4.4—Pearsons, scatter diagrams, eqn of y on x
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Topic 4—Statistics and probability

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