A car workshop logged the duration, in minutes, of 6 repair jobs completed on Monday: 25, 30, 22, 28, 35, 20. Work out the mean duration, giving your answer...
Question 1 Report
A car workshop logged the duration, in minutes, of 6 repair jobs completed on Monday: 25, 30, 22, 28, 35, 20.
- Work out the mean duration, giving your answer correct to 1 decimal place. (2)
- Work out the range of the durations. (1)
Answer Details
This question tests finding the mean of a small raw data set to a stated degree of accuracy, and finding its range.
(a) Adding all 6 durations and dividing by 6 gives the mean:
\[ \frac{25+30+22+28+35+20}{6} = \frac{160}{6} = 26.6\overline{6} \approx 26.7 \text{ minutes (1 dp)} \] [2 marks]
(b) The longest job took 35 minutes and the shortest took 20 minutes, so the range is
\[ 35 - 20 = 15 \text{ minutes} \] [1 mark]
Rounding only happens at the very last step here: the exact total of 160 is divided by 6 first, giving a recurring decimal, which is then rounded to 1 decimal place as the question asks.
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