Exam-Style Questions on Cumulative frequency
Problems on Cumulative frequency adapted from questions set in previous Mathematics exams.
This Cumulative Frequency graph shows the heights of 58 Scouts. Work out an estimate for the number of these Scouts with a height greater than 160cm.
The grouped frequency table gives information about the times, in minutes, that 90 commuters take to get home from work.
|Time (t minutes)||Frequency|
|\(0 \lt t \le 10\)||6|
|\(10 \lt t \le 20\)||32|
|\(20 \lt t \le 30\)||22|
|\(30 \lt t \le 40\)||10|
|\(40 \lt t \le 50\)||10|
|\(50 \lt t \le 60\)||7|
|\(60 \lt t \le 70\)||3|
(a) Complete the cumulative frequency table.
|Time (t minutes)||Cumulative frequency|
|\(0 \lt t \le 10\)|
|\(0 \lt t \le 20\)|
|\(0 \lt t \le 30\)|
|\(0 \lt t \le 40\)|
|\(0 \lt t \le 50\)|
|\(0 \lt t \le 60\)|
|\(0 \lt t \le 70\)|
(b) On the grid, draw the cumulative frequency graph for this information.
(c) Use your graph to find an estimate for the percentage of these commuters who take more than 45 minutes to get home from work.
The table shows the test marks for 31 students.
|5 ≤ p < 15||2|
|15 ≤ p < 25||3|
|25 ≤ p < 35||4|
|35 ≤ p < 45||3|
|45 ≤ p < 55||8|
|55 ≤ p < 65||8|
|65 ≤ p < 75||2|
|75 ≤ p < 85||1|
Marco drew this cumulative frequency graph using the data.
Make three criticisms of Marco’s graph.
The weights in grams of 98 mice are shown in the cumulative frequency diagram. The heaviest mouse weighted 160g.
(a) Write down the median weight of the mice.
(b) Find the percentage of mice that weigh 70 grams or less.
The same data is presented in the following table.
|Weights w grams||0 < w ≤ 40||40 < w ≤ 80||80 < w ≤ 120||120 < w ≤ 160|
(c) Find the value of p.
(d) Find the value of q.
(e) Use the values from the table to estimate the mean and standard deviation of the weights.
A second batch of mice are normally distributed with the same mean and standard deviation as those of the first group mentioned above.
(f) Find the percentage of the second batch of mice that weigh 70 grams or less.
(g) A sample of five mice is chosen at random from the second batch. Find the probability that at most three mice weigh 70 grams or less.
|IB Analysis and Approaches|
Gringe Hull Secondary School has students from Year 7 to Year 13. A group of 138 students in Year 9 were randomly selected and surveyed to find out how long it takes them to travel to school each morning. Their results are represented by the following cumulative frequency graph.
(a) Find the median number of minutes per day these Year 9 students spend travelling to school.
(b) Given that 20% of these Year 9 students spend more than \(k\) minutes per day travelling to school, find value of \(k\).
The same information is represented by the following table.
|Travelling time (m) in minutes||Frequency|
|0 < m ? 5||4|
|5 < m ? 10||10|
|10 < m ? 15||14|
|15 < m ? 20||\(p\)|
|20 < m ? 25||22|
|25 < m ? 30||21|
|30 < m ? 35||16|
|35 < m ? 40||\(q\)|
|40 < m ? 45||9|
|45 < m ? 50||6|
|50 < m ? 55||3|
|55 < m ? 60||1|
(c) Find the value of \(p\) and the value of \(q\).
There are 450 students in Year 9 at this school.
(d) Estimate the number of Year 9 students that spend less than 15 minutes travelling to school each day.
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