Calculate the mean, variance, and range for the grouped frequency distribution of haemoglobin levels.

a)
To calculate the mean, variance, and range for the grouped frequency distribution, we first need to find the midpoint ($x$) for each class interval and then calculate $fx$ and $fx^2$. The class intervals are given as 8.0-8.9, 9.0-9.9, etc. We will use the midpoints of these intervals.

Step 1: Determine the midpoints ($x$) for each class interval and calculate $fx$ and $fx^2$.
The total number of women ($N$) is $\sum f = 80$.

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