The table shows grouped journey times. Time, $t$ (min) $0

Question

The table shows grouped journey times. Time, $t$ (min) $0<t\le10$ $10<t\le20$ $20<t\le30$ $30<t\le40$ $40<t\le50$ Frequency 4 8 14 9 5 Calculate an estimate of the mean journey time. Calculate an estimate of the standard deviation, giving your answers correct to 3 significant figures.

Accepted Answer

(a) $25.75$ min; (b) $11.486$ min.

Sec 3/4 E Math T14-Q18 - Estimated mean and standard deviation for grouped data

Sec 3/4 E Math T14-Q18 - Estimated mean and standard deviation for grouped data

Solution:

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