Problems adapted from questions set for 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 information about the heights of 85 stalagmites.
|Height (\(h\) cm)||Frequency|
|\(10\lt h \le 15\)||9|
|\(15\lt h \le 20\)||13|
|\(20\lt h \le 25\)||18|
|\(25\lt h \le 30\)||22|
|\(30\lt h \le 35\)||15|
|\(35\lt h \le 40\)||8|
(a) Find the class interval that contains the median.
(b) On the grid below, draw a frequency polygon for the information in the table.
The table shows the marks earned by 200 students taking a Maths exam.
|Mark (n)||\(0\lt n \le 10\)||\(10\lt n \le 20\)||\(20\lt n \le 30\)||\(30\lt n \le 40\)||\(40\lt n \le 50\)||\(50\lt n \le 60\)||\(60\lt n \le 70\)||\(70\lt n \le 80\)|
(a) Use the data in the table above to complete the following cumulative frequency table
|Mark (n)||\(n \le 10\)||\(n \le 20\)||\(n \le 30\)||\(n \le 40\)||\(n \le 50\)||\(n \le 60\)||\(n \le 70\)||\(n \le 80\)|
(b) Draw the cumulative frequency curve on graph paper.
The top 5% of students will receive an A grade. The next 15% of students will receive a B grade and the next 30% will receive a C grade.
(c) Use your graph to estimate the lowest mark that B grade will be awarded for.
The table shows the amount of time, in months, taken to sell houses on the Happyland housing estate.
|Time (m months)||Frequency|
|0 < m ≤ 2||10|
|2 < m ≤ 5||21|
|5 < m ≤ 10||25|
|10 < m ≤ 15||20|
|15 < m ≤ 20||25|
(a) Draw a histogram for the information in the table.
(b) Find an estimate for the median.
This histogram shows information about the ages of 317 people attending a charity concert. The cost of tickets for children under 15 years of age are half price. If a full price ticket was £18, estimate the total income of all 317 ticket sales.
|IB Analysis and Approaches|
A TV company surveyed 88 of its employees to find out how much time they spend travelling to work on a given day. The results of the survey are shown in the following cumulative frequency diagram.
(a) Find the median number of minutes spent travelling to work.
(b) Find the interquartile range.
(c) Find the number of employees whose travelling time is within 20 minutes of the median.
(d) Only 10% of the employees spent less than k minutes travelling to work. Find the value of k.
The results of the survey can also be displayed on the following box-and-whisker diagram.
(e) Write down the value of a.
(f) Find the value of b.
(g) Travelling times of less than p minutes are considered outliers. Find the value of p .
This cumulative frequency graph shows the speeds in kmh-1 of cyclists passing a certain point on a race track.
(a) Estimate the minimum possible speed of one of these cyclists.
(b) Find the median speed of the cyclists.
(c) Write down the 65th percentile.
(d) Calculate the interquartile range.
(e) Find the number of these cyclists that were travelling faster than 22 kmh-1
The table shows the speeds of these cyclists.
|Speed of Cyclists (s)||Number of Cyclists|
|\(0 \lt s \le 5\)||0|
|\(5 \lt s \le 10\)||\(a\)|
|\(10 \lt s \le 15\)||8|
|\(15 \lt s \le 20\)||20|
|\(20 \lt s \le 25\)||16|
|\(25 \lt s \le 30\)||5|
|\(30 \lt s \le 35\)||\(b\)|
(f) Find the value of \(a\) and of \(b\)
(g) Write down the modal class.
(h) Write down the mid-interval value for the modal class.
(i) Use your graphic display calculator to calculate an estimate of the mean speed of these cyclists.
(j) Use your graphic display calculator to calculate an estimate of the standard deviation of the speeds of these cyclists.
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