Cumulative frequency

Sixty athletes enter a cross-country race. Their finishing times are recorded and are shown in the table below:

Copy the table and calculate the values for the cumulative frequency.

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Sixty athletes enter a cross-country race. Their finishing times are recorded and are shown in the table below:

Draw a cumulative frequency curve of the results.

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Sixty athletes enter a cross-country race. Their finishing times are recorded and are shown in the table below:

Show how your graph could be used to find the approximate median finishing time.

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Sixty athletes enter a cross-country race. Their finishing times are recorded and are shown in the table below:

What does the median value tell us?

• The median value tells us that the finishing time of most athletes is 2.8 hours.

  
  

• The median value tells us that the finishing time of most athletes is 1.8 hours.

  
  

• The median value tells us that the finishing time of most athletes is 2 hours.

  
  

• The median value tells us that the finishing time of most athletes is 3 hours.

  
  

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Three Mathematics classes take the same test in preparation for their final examination. Their raw scores are shown in the table below:

Class A 12, 21, 24, 30, 33, 36, 42, 45, 53, 53, 57, 59, 61, 62, 74, 88, 92, 93

Class B 48, 53, 54, 59, 61, 62, 67, 78, 85, 96, 98, 99

Class C 10, 22, 36, 42, 44, 68, 72, 74, 75, 83, 86, 89, 93, 96, 97, 99, 99

Draw a cumulative frequency curve for Class A.

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Three Mathematics classes take the same test in preparation for their final examination. Their raw scores are shown in the table below:

Class A 12, 21, 24, 30, 33, 36, 42, 45, 53, 53, 57, 59, 61, 62, 74, 88, 92, 93

Class B 48, 53, 54, 59, 61, 62, 67, 78, 85, 96, 98, 99

Class C 10, 22, 36, 42, 44, 68, 72, 74, 75, 83, 86, 89, 93, 96, 97, 99, 99

Using the results in the previous question, find the interquartile range of Class A taking the Mathematics test.

• IQR for Class A = 1.5

• IQR for Class A = 29

• IQR for Class A = 34

• IQR for Class A = 51.5

Three Mathematics classes take the same test in preparation for their final examination. Their raw scores are shown in the table below:

Class A 12, 21, 24, 30, 33, 36, 42, 45, 53, 53, 57, 59, 61, 62, 74, 88, 92, 93

Class B 48, 53, 54, 59, 61, 62, 67, 78, 85, 96, 98, 99

Class C 10, 22, 36, 42, 44, 68, 72, 74, 75, 83, 86, 89, 93, 96, 97, 99, 99

Draw a cumulative frequency curve for Class B.

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