Range/Interquartile Range
How do you calculate the range of a set of data?
Range is the highest value less the lowest value in the range.
Range = Highest value - Lowest value
What is the mode of the following data set?
66, 77, 12, 34, 11, 15, 67, 86, 12, 15, 34, 64, 15
15
What is the mean of the following data set?
5, 5, 25, 30, 35
Mean is 20
What is the median value of a set of data?
The middle value of a set of data.
What four things should you always check are shown on your Bar Chart?
SALT
Scale, Axis, Labels, Title
How do you calculate the interquartile range of a data set?
The interquartile range is calculated by subtracting the lower quartile Q1 from the upper quartile Q3
Interquartile range = Q3 - Q1
How do you calculate the mode of a data set?
Mode is the value that appears the most often
How do you calculate the mean of a set of data?
Sum all the numbers in the data set and divide the total by the number of values in the data set.
What is the median of the following data set?
12, 67, 34, 25, 87, 22, 34, 66, 54, 34, 36
Median = 34
If you wish to compare what proportions of your day you spend watching tv, playing sport, sleeping, attending school, doing homework, etc. What type of chart would be most suitable?
Pie Chart - as it shows the percentage time each activity takes.
What is the range of; 56, 45, 90, 12, 45, 77, 45
78
What is the mode of the following frequency distribution;
Value 12 15 16 17 18 19 20
Frequency 3 4 6 2 1 5 2
16
How do you calculate the mean of a frequency distribution?
Multiply every value (x) in the by its frequency and add all these values. Then divide your solution by the sum of the frequencies
How do you calculate the Median of a data set?
Put the numbers in ascending order. Count the number of values in the data set (n). Get half of (n+1).
This gives you the position where the median lies. If it is a whole number count up the data set to that position and the value there is your median.
If it is not a whole number e.g. 10.5, get the values at either side of this position (values 10 and 11) add them together and divide their sum by 2.
What type of graph is most commonly used to represent a frequency distribution?
A histogram
If the upper quartile Q3 of a data set is 56 and the lower quartile Q1 of a data set is 12 what is the interquartile range of the data set?
Interquartile range = Higher Quartile - Lower Quartile
Answer = 44
What class does the mode lie in for the following grouped frequency distribution;
Class 0-5 5-10 10-15 15-20
Frequency 14 17 16 11
Mode lies in the 5-10 class
How do you estimate the mean of a grouped frequency distribution?
First calculate the mid-interval value of each class/grouping in the frequency distribution. Then multiply this mid-interval value with its corresponding frequency. Sum these values, then divide this total by the sum of the frequencies.
What is the median of the following frequency distribution;
Value 12 15 16 17 18 19 20
Frequency 3 4 6 2 1 5 2
Answer is 16
In a histogram on what axis does the frequency appear?
Vertical Axis