| Date | May 2011 | Marks available | 4 | Reference code | 11M.1.sl.TZ1.2 |
| Level | SL only | Paper | 1 | Time zone | TZ1 |
| Command term | Find | Question number | 2 | Adapted from | N/A |
Question
The table below shows the frequency distribution of the number of dental fillings for a group of \(25\) children.
Find the value of \(q\) .
Use your graphic display calculator to find
(i) the mean number of fillings;
(ii) the median number of fillings;
(iii) the standard deviation of the number of fillings.
Markscheme
\(q = 25 - (4 + 3 + 8 + 4 +1)\) (M1)
Note: Award (M1) for subtraction from \(25\) of all values from the table.
\( = 5\) (A1) (C2)
[2 marks]
(i) \(2.2\) (A2)(ft) (C2)
Note: Award (M1) for use of mean formula with correct substitution. Follow through from part (a), irrespective of whether working is shown.
(ii) \(2\) (A1) (C1)
(iii) \(1.39\) (A1)(ft) (C1)
Note: Follow through from part (a), irrespective of whether working is shown. Award (A1) for \(1.38\).
[4 marks]
Examiners report
Part b was not well answered by the majority of candidates, indicating that the use of the GDC is not a natural tool for answering this type of question. Many students ignored the frequencies when finding the mean, median, and standard deviation.
Part b was not well answered by the majority of candidates, indicating that the use of the GDC is not a natural tool for answering this type of question. Many students ignored the frequencies when finding the mean, median, and standard deviation.
