Exploring data

What is a variable?

A variable is the property being measured as part of your statistical investigation

State what the following symbols mean:

1. x

2. n

3. f

4. ∑x

1. Individual results

2. Total number of variables in the sample

3. Frequency is the number of occurrences of each x

4. The sum of (sigma) the x’s

Name 4 types of data (give an example)

1. Categorical data (favourite flavour of yoghurt)

2. Discrete numerical data (number of people in a household)

3. Continuous numerical data (height of a person)

4. Ranked data/ordered data (used to find median, quartiles, max, min, range)

Name 3 ways to tabulate data

1. Frequency tables

2. Grouping data in frequency tables

3. Stem and leaf diagrams

Name 3 measures of central tendency

1. Mean

   μ is population mean = not a statistic, parameter

   x bar (x̄)

2. Median

   median is the (n + 1)/2 th value

3. Mode