Initial Diagnostic Audit - Unit E4: Measures of Variation Do NOT use a calculator for any questions in the audit unless specifically told otherwise
Section E4.1 - Cumulative Frequency
You may use a calculator for this section.
The cumulative frequency polygon shows the results of asking a group of 120 students "How far do you travel to college each day?"
1. What is the median value?
2. What is the upper quartile value?
3. What is the lower quartile value?
4. What is the interquartile range?
5. What is the range between the 20th and 80th percentiles?
Section E4.2 - Box and Whisker Plots
A box and whisker plot for a set of data values is shown below.
6. What is the median value?
7. What is the upper quartile value?
8. What is the inter-quartile range?
9. What is the smallest value?
10. What is the range of the data?
Section E4.3 - Standard Deviation
You may use a calculator for this section.
11. What is the standard deviation (to one decimal place) of the following sets of numbers.
(a) 4, 5, 8, 11, 12
(b) 8, 8, 8, 8, 8
12. The numbers of students travelling on the school bus each day over the past term have mean value 20.4 and standard deviation 3.2.
For the new term the bus fares have been reduced. The loadings for the first 15 days of operation were:
22, 25, 24, 22, 26, 27, 25, 24, 26, 27, 28, 27, 25, 29, 28
(a) Find the mean of this set of data. Give your answer to 1 d.p.
(b) Find the standard deviation of this data. Give your answer to 2 decimal places.
(c) Has the reduction in fares been successful? Yes No
