The Median

Question 1

What is the rule for finding the position of the median given the number of items, n?

Answer 1

position of median = (n+1) / 2

Question 2

When is a cumulative frequency step polygon used?

Answer 2

When the data is grouped and discrete.

Question 3

What is the method of interpolation for working out the median of grouped data?

Answer 3

1. Work out the cumulative frequency of the data.
2. Work out the position of the median.
3. Calculate (the position of the median - the cumulative frequency of the group before).
4. Calculate (step 3 / frequency of group containing median.)
5. Calculate (step 4 x class width)