The table shows the weights, to the nearest kilogram, of twelve students in a Further Mathematics class Weight in kg 55 57 59 61 63 No of students 2 1 2 4 3...

Assessment: WAEC SSCE - General Mathematics - 1989 (Objective) Subject: General Mathematics

Question 1 Report

The table shows the weights, to the nearest kilogram, of twelve students in a Further Mathematics class

Weight in kg 55 57 59 61 63
No of students 2 1 2 4 3

(a) Draw a bar chart to illustrate the above information;

(b) What is (i) the mode; (ii) the median of the distribution?

(c) Calculate the mean weight correct to the nearest kilogram.

Answer Details

(a) Bar chart

graph
Bar chart showing the frequency of each weight. The bars are separate because the weights are discrete values.

(b)(i) Mode

The highest frequency is 4, corresponding to a weight of 61 kg.

\[\boxed{\text{Mode}=61\text{ kg}}\]

(b)(ii) Median

There are \(12\) students. Therefore, the median is the mean of the 6th and 7th observations.

The ordered weights are:

\[55,\ 55,\ 57,\ 59,\ 59,\ \underbrace{61,\ 61}_{\text{6th and 7th}},\ 61,\ 61,\ 63,\ 63,\ 63\]

\[\text{Median}=\frac{61+61}{2}=\boxed{61\text{ kg}}\]

(c) Mean weight

\[\begin{aligned}\sum f&=2+1+2+4+3=12,\\\sum fx&=55(2)+57(1)+59(2)+61(4)+63(3)\\&=110+57+118+244+189\\&=718.\end{aligned}\]

\[\text{Mean}=\frac{\sum fx}{\sum f}=\frac{718}{12}=59.833\ldots\text{ kg}\]

\[\boxed{\text{Mean weight}=60\text{ kg, correct to the nearest kilogram}}\]

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