1. Single Variable Data Analysis
Vocabulary:
data mean median
mode range average
measures of location appropriate
measures of spread categorical
measures of location numerical
context statistics outliers
clusters gaps inclusion
analyse interpret investigate
random sample
summary statistics
Single Variable Data Analysis

2. How tall are people in our class?
Use the height chart at the back of the room to measure your height (working in pairs) then write your height on the board to the right.
When everybody is finished, work with your partner to come up with a paragraph describing the heights of everybody in this class.

3. The Mean

7. The Mode
The mode is the score that occurs most often, or the score with the highest frequency. It may be used for numerical or categorical data. It is the only measure that can be used for categorical data.

9. The Range
The range is the simplest measure of the spread of scores. It is calculated using: range = highest score − lowest score.

12. The Median
The median is the middle score after the scores have been arranged in ascending order (that is, from smallest to largest). The median divides the data into two parts such that there are equal numbers of scores below it and above it. The median cannot be used for categorical data.

18. Which one should I use?
The mean, mode and median are measures of central tendency; that is, as single numbers that are central or typical of all the numbers. Often we need to consider which measure is the most appropriate in a given situation. There is no general rule that can be used. For categorical data, the mode is the only measure that can be used. The mean has the disadvantage of being affected by extremely large or small values. Very small or very large atypical scores are called outliers. In some cases it may be useful to ignore outliers when calculating the mean.

29. Random Sampling
Often it is not feasible to investigate the properties of a whole population so we only collect data from a small part of the population. The part of the population investigated is called a sample. We use the properties and characteristics of the sample to provide an estimate of the properties and characteristics of the population.
Repeat for each group of 20 students, then compare answers