CAIE IGCSE Mathematics Extended E9.3.2 Calculate an estimate of the mean for grouped discrete or grouped

Practise estimating the mean from grouped tables by using class midpoints, frequency products and the total frequency.

Exam points

choose class midpoints from grouped intervals before multiplying by frequency
calculate Σfx and divide by the total frequency to estimate the grouped mean
use interval boundaries correctly when selecting representative midpoint values

[Maximum number: 4]

The 200 students also estimate the total area, $A \mathrm{~m}^{2}$ , of the windows in the classroom. The table shows their results.

Table for Question E9.3.2 Calculate an estimate of the mean for grouped discrete or grouped question 1 — CAIE IGCSE Mathematics Extended

Calculate an estimate of the mean.

You must show all your working.

___ m^2

Mid-values 40, 80, 125, 200 soi
$\sum fx$ with correct frequencies and x's in correct intervals or on boundaries of correct intervals
$\div 200$
106 nfww
SC2 for correct answer without working.

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E9.3.2 Calculate an estimate of the mean for grouped discrete or grouped question 1