Answers − Frequency Diagrams and Polygons

For each question enter the Midpoints below and then plot a Frequency Diagram and Frequency Polygon onto some graph paper

1.  Following is the Weight of a random item

Weight kg Frequency f 2≤W≤5 4 5≤W≤8 8 8≤W≤11 10 11≤W≤14 3

  (a) For each range of Marks work out the midpoint x

Weight kg f Midpoint x 2≤W≤5 4 3.5 5≤W≤8 8 6.5 8≤W≤11 10 9.5 11≤W≤14 3 12.5

2.  Following is the cost of a fancy MP3 player

Cost £ Frequency f 0≤C≤50 2 50≤C≤100 8 100≤C≤150 7 150≤C≤200 3

  (a) For each range of Marks work out the midpoint x

Cost £ f Midpoint x 0≤C≤50 2  25  50≤C≤100 8  75  100≤C≤150 7  125  150≤C≤200 3  175

3.  Here are the number of Gadgets in each household, in a small survey.

Number of Gadgets Frequency f 0≤G≤4 4 4≤G≤8 10 8≤G≤12 7 12≤G≤16 3

  (a) For each range of Marks work out the midpoint x

Number of Gadgets f Midpoint x 0≤G≤4 4  2  4≤G≤8 10  6  8≤G≤12 7  10  12≤G≤16 3  14

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