Edexcel IGCSE Math A 6.2.C estimated mean for grouped data

Practise estimated-mean questions by finding midpoints, multiplying by frequencies and dividing by the total frequency carefully.

Exam points

Find class midpoints from grouped intervals before estimating the total.
Multiply each midpoint by its frequency and divide by the total frequency.
State that the result is an estimate because grouped data uses interval midpoints.

[Maximum number: 4]

The table shows information about the weights, in kilograms, of 40 babies.

Work out an estimate for the mean weight of the 40 babies. kg

One of the 40 babies is going to be chosen at random.

$(12\times2.5)+(16\times3.5)+(9\times4.5)+(2\times5.5)+(1\times6.5)$ 30+56+40.5+11+6.5=144

Estimated mean:
$\frac{144}{40}=3.6$

Final answer:
3.6

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