Booklet 2: Data Analysis Flashcards
Measure of central tendency definition
An average of a data set
Mean definition
- The score commonly known as the average
- To calculate, you add all the numbers in the data set together and divide by the total amount of results
Median definition
- The middle value when raw data is placed in order from smallest to largest
- It is not affected by extreme values as they are marginalised
Mode definition
- The value or event that occurs most frequently
- This measurement is a basic measure of central tendency
Strength of the Mean
- POINT - All of the data is used to calculate the answer
- COMMENT - Therefore it is an accurate representation of the data
Weakness of the Mean
- POINT - Extreme scores can distort the value
- COMMENT - Therefore it is not an appropriate measure of central tendency if our data set is skewed
Strength of the Median
- POINT - Extreme scores do not distort the value
- COMMENT - Therefore it is a robust measure of central tendency if our data set is skewed by extreme values
Weakness of the Median
- POINT - It is difficult and time consuming to calculate with a large data set
- POINT - It is a less representative measure of central tendency because it does not depend on all the items in the data
Strength of the Mode
- POINT - It is the only measure of central tendency we can use when the data is not numerical
- COMMENT - Therefore it allows for analysis of the most commonly occurring category
Weakness of the Mode
- POINT - This measure of central tendency may not accurately reflect the data
- COMMENT - Therefore if there is no most popular answer, this measure of central tendency is effectively useless
What is Discrete data
Data that can be placed into separate categories
What is Continuous Data
Data that cannot be placed into distinct categories and can be presented on a number line
What are the 5 graphs you need to know
- Bar Charts
- Pie Charts
- Histograms
- Line Graphs
- Scatter Graphs
Which of the graphs represent Discrete data
- Bar Charts
- Pie Charts
Which of the graphs presents Continuous data
- Histograms
- Line Graph
- Scatter Graph
What is the criteria for drawing a Bar Chart
- Used for discrete data
- Columns do not touch
- Useful for comparing groups of data
- The mean/frequency is on the Y axis
- The category is on the X axis
- Labels on each axis
- Title
What is the criteria for drawing a Pie Chart
- Used for discrete data
- Shows relative contribution to overall total
- Used for 6 categories or fewer
- Useful when data is showing a percentage
What is the criteria for drawing a Line Graph
- Used for continuous data
- Used for comparing 2 or more conditions
- Good for looking at changes over time
- Continuous scale is on the X axis
- Frequency/measurement is on the Y axis
- Data points are connected with a straight line
- Labels at the end of the lines
What is the criteria for drawing a Scatter Diagram
- Used for continuous data
- Used for measuring the relationship between two variables
- Data from one variable is presented on the X axis and the other variable on the Y axis
- Shows a positive, negative or no correlation
What is the criteria for drawing a Histogram
- Used for continuous data
- Columns touch
- The area of the columns shows the frequency
- The frequency density is on the Y axis
- The continuous scale is on the X axis
- Requires class boundaries, class width and frequency density
How do you calculate frequency density
Frequency Density = Frequency / Class Width
Structure for Exam Q:
“Outline a conclusion from the table”
- State a finding using raw data
- Explain what this data means in the context of the study
- Making an inference as to why
Structure for Exam Q:
“Outline a finding from the table”
- State a simple finding from the table or graph including the numbers if possible
- Make sure it is in context of the data in the question
