Calculate the mean, variance, and range from a frequency distribution of haemoglobin levels.

a)
To calculate the mean, variance, and range from the frequency distribution, we first need to find the midpoint ($x$) for each class interval, and then calculate $fx$ and $fx^2$.

Step 1: Create a table with midpoints, $fx$, and $fx^2$.
The class intervals are given as 8.0-8.9, 9.0-9.9, etc. The midpoint $x$ for a class $a-b$ is $\frac{a+b}{2}$.

| Haemoglobin (g/100ml) | Number of Women ($f$) | Midpoint ($x$) | $fx$ | $x^2$ | $fx^2$ | | :-------------------- |