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Date May 2018 Marks available 1 Reference code 18M.1.SL.TZ1.T_6
Level Standard Level Paper Paper 1 (with calculator from previous syllabus) Time zone Time zone 1
Command term Write down Question number T_6 Adapted from N/A

Question

In a high school, 160 students completed a questionnaire which asked for the number of people they are following on a social media website. The results were recorded in the following box-and-whisker diagram.

The following incomplete table shows the distribution of the responses from these 160 students.

Write down the median.

[1]
a.

Complete the table.

[2]
b.

Write down the mid-interval value for the 100 < x ≤ 150 group.

[1]
c.i.

Using the table, calculate an estimate for the mean number of people being followed on the social media website by these 160 students.

[2]
c.ii.

Markscheme

* This question is from an exam for a previous syllabus, and may contain minor differences in marking or structure.

180   (A1) (C1)
[1 mark]

a.

36, 24     (A1)(A1) (C2)

Note: Award (A0)(A1) for two incorrect values that add up to 60.

[2 marks]

b.

125 (accept 125.5)     (A1)

c.i.

4 × 25 + 36 × 75 + 34 × 125 + 46 × 175 + 24 × 225 + 16 × 275 160      (M1)

Note: Award (M1) for correct substitution of their mid-interval values, multiplied by their frequencies, into mean formula.

=156 (155.625)     (A1)(ft) (C3)

Note: Follow through from parts (b) and (c)(i).

[3 marks]

c.ii.

Examiners report

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

Syllabus sections

Topic 4—Statistics and probability » SL 4.2—Histograms, CF graphs, box plots
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Topic 4—Statistics and probability » SL 4.3—Mean, median, mode. Mean of grouped data, standard deviation. Quartiles, IQR
Topic 4—Statistics and probability

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