EXN.2.SL.TZ0.1

pestleMathematicsAASLPaper 2EXN· sl-4-3-mean-median-mode-mean-of-grouped-data-standard-deviation-quartiles-iqrsource ↗

A data set consisting of $16$ test scores has mean $14.5$ . One test score of $9$ requires a second marking and is removed from the data set.

Find the mean of the remaining $15$ test scores.

Markscheme / solution

* This sample question was produced by experienced DP mathematics senior examiners to aid teachers in preparing for external assessment in the new MAA course. There may be minor differences in formatting compared to formal exam papers.

$\frac{Σ_{i = 1}^{16} x_{i}}{16} = 14.5$ (M1)

Note: Award M1 for use of $\bar{x} = \frac{Σ_{i = 1}^{n} x_{i}}{n}$ .

$\Rightarrow Σ_{i = 1}^{16} x_{i} = 232$ (A1)

new $\bar{x} = \frac{232 - 9}{15}$ (A1)

$= 14.9 (= 14.8 \bar{6}, = \frac{223}{15})$ A1

Note: Do not accept 15.

[4 marks]

Examiners’ report

[N/A]