Cumulative frequency Example The frequency table shows the

Cumulative frequency Example The frequency table shows the examination marks of 80 students. a) Draw a cumulative frequency table and cumulative frequency curve to represent this data. b) Find the median and interquartile range for this data. Mark Frequency 0 -10 2 10 -20 4 20 -30 7 30 -40 14 40 -50 23 50 -60 13 60 -70 8 70 -80 6 80 -90 2 90 -100 1 Total 80

Example The table below shows the results in a recent survey on the weights of boys in a particular school. Weight (w kg) Frequency 11 22 8 a) Draw a cumulative frequency table and cumulative frequency curve to represent this data. b) Find the median and interquartile range for this data. 5

Example The masses of 150 girls were obtained and placed in the table below. Mass (kg) Frequency 35 – 40 5 40 – 45 24 45 – 50 30 50 – 55 55 – 60 28 60 – 65 27 26 65 – 70 7 70 – 75 3 a) Draw a cumulative frequency polygon which represents this data b) Find the median mass for these girls c) Find the interquartile range for this data d) What percentage had a weight less than 47 kg?

Example The table below shows the age distribution of 200 people in a factory Age Frequency 15 – 20 20 – 25 25 – 30 30 – 40 40 – 50 50 – 60 18 59 63 20 25 15 a) Draw a cumulative frequency curve to represent this data b) Use the curve to estimate the median c) What is the interquartile range for this data?