Problems adapted from questions set for previous Mathematics exams.
The following table shows the time taken by fifty people to answer their emails one day.
|Time, t minutes||Number of people|
|0 < t ≤ 10||5|
|10 < t ≤ 20||12|
|20 < t ≤ 30||13|
|30 < t ≤ 40||15|
|40 < t ≤ 50||5|
(a) In which class interval is the median?
(b) How many people took more than 20 minutes?
(c) What is the modal class interval?
(d) Find an estimate for the mean time taken showing all of your working.
The following table show data collected by a researcher about the length of monitor lizards living in a park in Bangkok.
|\(0\lt l \le 50\)||9|
|\(50\lt l \le 100\)||13|
|\(100\lt l \le 150\)||22|
|\(150\lt l \le 200\)||19|
|\(200\lt l \le 250\)||11|
|\(250\lt l \le 300\)||3|
(a) Which is the modal group?
(b) Calculate an estimate for the mean lizard length.
(c) The researcher claims that the range of lengths must lie between 2m and 3m. Explain how the researcher came to this conclusion.
The following table shows the number of times people in a sample group visited the cinema in a six month period.
One of the frequencies is missing.
Midpoints are used to work out an estimate for the mean number of visits.
The mean is calculated to be 7.25.
Work out the missing frequency.
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.
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