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Date	May 2018	Marks available	2	Reference code	18M.1.sl.TZ1.2
Level	SL only	Paper	1	Time zone	TZ1
Command term	Find	Question number	2	Adapted from	N/A

Question

Each month the number of days of rain in Cardiff is recorded.
The following data was collected over a period of 10 months.

11 13 8 11 8 7 8 14 x 15

For these data the median number of days of rain per month is 10.

Find the value of x.

[2]

Find the standard deviation

[2]

b.i.

Find the interquartile range.

[2]

b.ii.

Markscheme

\(\frac{{x + 11}}{2} = 10\) (M1)

Note: Award (M1) for correct substitution into median formula or for arranging all 9 values into ascending/descending order.

\(\left( {x = } \right)\,\,9\) (A1) (C2)

[2 marks]

2.69 (2.69072…) (A2)(ft)

Note: Follow through from part (a).

[2 marks]

b.i.

13 − 8 (M1)
Note: Award (M1) for 13 and 8 seen.

= 5 (A1)(ft) (C4)
Note: Follow through from part (a).

[2 marks]

b.ii.

Examiners report

[N/A]

b.i.

[N/A]

b.ii.

Syllabus sections

Topic 2 - Descriptive statistics » 2.5

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11M.2.sl.TZ2.1B.b: Use your graphic calculator to find (i) \({\bar S}\), the mean of \(S\) ; (ii) ...
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18M.2.sl.TZ2.2e: Find the number of buses that travelled a distance less than or equal to 12 000 km.
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14M.1.sl.TZ2.5a: Write down the median rainfall.
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17M.2.sl.TZ1.5b: Find the median test grade of the students.
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16N.2.sl.TZ0.1b: (i) \({\bar x}\), the mean number of hours spent on social media; (ii) \({\bar y}\),...
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17N.2.sl.TZ0.1c.ii: Use your graphic display calculator to estimate the standard deviation of \(N\).
18M.1.sl.TZ1.2b.i: Find the standard deviation
18M.2.sl.TZ2.2c: Hence write down the interquartile range.
18M.2.sl.TZ2.2b.iii: Use the cumulative frequency curve to find the upper quartile.
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09N.1.sl.TZ0.1b: Write down the mode.
11M.1.sl.TZ1.2b: Use your graphic display calculator to find(i) the mean number of fillings;(ii) the...
11M.1.sl.TZ2.6a: Find the mean number of goals scored per match.
14M.2.sl.TZ2.3c: Find an estimate of the mean time people took to drink their coffee.
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14M.1.sl.TZ1.2b: For these grades, find the median;
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14N.1.sl.TZ0.3b: Write down (i) the number of hens on the farm; (ii) the modal number of eggs laid.
14N.1.sl.TZ0.3c: Calculate (i) the mean number of eggs laid; (ii) the standard deviation.
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17N.1.sl.TZ0.1a.i: For the students in this group find the mean age;
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17N.2.sl.TZ0.1e.i: Write down the null hypothesis for this test;
18M.1.sl.TZ1.2a: Find the value of x.
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12N.1.sl.TZ0.3a: Calculate the exact value of the mean length.
12N.1.sl.TZ0.11c: Calculate an estimate of the mean annual snowfall.
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07M.1.sl.TZ0.2c: Write down three different integers whose mean is 10.
07M.1.sl.TZ0.6b: Write down the median of the numbers in part (a).
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17N.1.sl.TZ0.1a.ii: For the students in this group write down the median age.
17N.2.sl.TZ0.1a: State whether \(N\) is a discrete or a continuous variable.
17N.2.sl.TZ0.1b.i: Write down, for \(N\), the modal class;
17N.2.sl.TZ0.1c.i: Use your graphic display calculator to estimate the mean of \(N\);
10M.1.sl.TZ2.5a: Write down an equation in terms of p and q.
10N.1.sl.TZ0.7b.i: Use your graphic display calculator to find an estimate for the mean weight.
11N.2.sl.TZ0.1b: Use your graphic display calculator to find an estimate for (i) the mean speed of the...
12N.1.sl.TZ0.11a: Write down the modal class.
12N.2.sl.TZ0.1a: (i) Write down the mean score in Round 1. (ii) Write down the standard deviation in Round...
12M.1.sl.TZ1.1b: Find y ;
12M.2.sl.TZ2.3b: State the modal group.
09N.1.sl.TZ0.1c: Find the median.
09N.2.sl.TZ0.4A, a, i: Use your graphic display calculator to find the mean number of trees.
13M.1.sl.TZ2.14a: Calculate the value of p.
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07M.1.sl.TZ0.2b: The boxplot below shows the statistics for a set of data. For this data set write down the...
SPM.1.sl.TZ0.4a: Write down the coordinates of the mean point \((\bar x{\text{, }}\bar y)\).
07N.2.sl.TZ0.4i.a: State the modal group.
08N.1.sl.TZ0.6c: Find an estimate of the mean weight of the members of the club.
08M.1.sl.TZ1.2a: Write down the median age.
08M.1.sl.TZ2.5d: Find how many houses have a number of bedrooms greater than one standard deviation above the...
13N.1.sl.TZ0.1c: Use your graphic display calculator to find (i) the mean number of passengers per...
15M.2.sl.TZ1.3g: The table shows the speeds of these vehicles travelling past the hospital gate. (i) ...
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16N.1.sl.TZ0.2a: Giving your answer to one decimal place, write down the value of (i) the median level of...
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11N.1.sl.TZ0.2a: Write down the modal grade.
09N.1.sl.TZ0.1a: Find the value of T.
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08M.2.sl.TZ1.3a: Write down (i) the mean temperature; (ii) the standard deviation of the temperatures.
09N.2.sl.TZ0.4A, a, iii: Use your graphic display calculator to find the mean depth of snow.
10M.2.sl.TZ2.2b.ii: Write down for this set of data the mean distance, \(\bar d\).
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15M.1.sl.TZ1.2a: Find the median grade.
16M.1.sl.TZ2.14b: For this group of students, the estimated mean number of hours spent practising mathematics...
17M.2.sl.TZ1.5c: Find the interquartile range.
17M.2.sl.TZ1.5a.ii: Calculate the standard deviation.
16N.2.sl.TZ0.1c: Plot the point \((\bar x,{\text{ }}\bar y)\) on your scatter diagram and label this point M.
17N.2.sl.TZ0.1g: State the result of the test. Give a reason for your answer.
18M.1.sl.TZ2.12a: Write down the mid-interval value for 10 ≤ t < 15.
18M.2.sl.TZ2.2f: Find the value of m.

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