# Statistics and Probability

Please find links to key chapters from this area - Statistics, Descriptive and Applications, of the course below. In addition, here is a growing collection of practice questions for you to use as a review exercise for the whole unit. Currently there are 5 exam style questions worth 38 marks and should be completed in about 40 minutes, before looking at the solutions.

### What are the different types of data?

Data is usually described as either qualititative (using words) or quantitative (using numbers). Within the quantitative category, data is either discrete or continuous.  Statistical Concepts

### What is an outlier?

Outliers are data points that differ significantly from the others Statistical Concepts

### What is cumulative frequency?

Cumulative frequency is a running total of all frequencies. It is usually shown by drawing an 'S' shaped graph Cumulative Frequency & Box Plots

### How do box plots work?

Box plots display a five number summary of a data set. They are very useful for making comparisons between data sets.  Cumulative Frequency & Box Plots

### What is Spearman correlation used for?

Spearman's Rank Correlation Coefficient is used to measure the relationship between two variables by ranking them. Find out more here: Spearman's Rank Correlation Coefficient 4.10

• ### 4.1 Statistical concepts

Key Concepts In this unit you should learn to… … …     Essentials   1. Types of Data Discrete and Continuous Data, what is a data, how do we ensure we minimise bias in our data?   2. Sampling vs Population Why might you want to take a sample...

• ### 4.3 Central tendency and Dispersion

Mean, Mode, Median, Range, Variance, Standard Deviation Measures of central tendency, such as the mean, median and mode, are very useful ways of respresenting large amounts of data with just one value. They can be very useful in forming conclusions...

• ### 4.4 Bivariate data & Linear Correlation

This topic is all about looking for relationships between variables. Does life expectancy depend on GDP? By collecting 2 variables about the things we survey we can use scatter graphs to represent the data and then look for correlation and...

• ### 4.5 Probability

Key Concepts In this unit you should learn to… … …     Essentials   Slides Gallery - Probability Part 1 Mode: carousel Thumb width: 48px Layout: row     1. Ideas, language and notation - Part 1 This is an introduction to the key ideas and terms...

• ### 4.7 Discrete random variables

Random variables are a set of possible outcomes from a random experiment. They can either be discrete or continuous. In this chapter we will find out more about discrete random variables, how they can be represented, displayed and analysed.

• ### 4.8 Binomial Distribution

Key Concepts In this unit you should learn to… … …     Essentials   1. Types of Data Discrete and Continuous Data, what is a data, how do we ensure we minimise bias in our data?   2. Sampling vs Population Why might you want to take a sample...

• ### 4.9 Normal Distribution

The normal distribution is a fascinating, naturally occurring phenomenon that has very relevant applications to understanding the world around us. When a data set is normally distributed it has some key properties that allow us to make predictions...

• ### 4.11 Chi Squared Independence tests

The chi squared independence tests is a widely used technique for looking for a relationship between variables that are categorical. We can use a scatter graph to look for a relationship between GDP and life expectancy, but what about GDP and...