4] Probability % Z-Scores Flashcards
What is inferential statistics
It is making estimates about a population from a sample of data
What is a core component of inferential statistics
Probability
What is a theory
An explanation of an aspect of the natural world that can be or that has been repeatedly tested
What do we use to test a theory
A testable hypothesis
What does a testable hypothesis do
They are capable of disproving or invaliding a theory
How do we test a hypothesis
Make a basic research questions, then collect data from a sample and preform a statistical analysis
How do we know a theory is false
Our observations contradict our predictions
How do we know a theory is true
Our observations are consistent with our prediction
What is a P-Value
It is a probability value
What is the simple probability formula
The number of favourable outcomes / total number of possible outcomes
What do standardised scores (z-scores) do
They allow us to compare scores from different scales
E.g: Z-Scores
What are Z-Score
They express raw data as standard deviations away from the mean, allowing us to know where a person falls on a distribution
How do Z-Scores work
They transform raw scores into standard deviation units, their distribution will always have the mean 0 and SD 1
What is the Z-Scores formula
Raw score (x) - Mean / Standard Deviation (SD)
What parts are involved in interpreting Z-Scores
1] Sign of the z-scores
2] Numerical value
1] Sign of the z-scores
Positive= The person is above average
Negative= The person is below average
0= The person is exactly average
2] Numerical value
Is an indication of how far the z-score is from the mean, I’m standard deviations
The large the value the more extreme the score is in distribution (further from the mean)
Formula for calculating raw scores from Z-Scores
Z-Score x SD then + this to the mean
Characteristics of normal distribution
1] Bell shaped
2] Mean, median and mode are equal and at the centre of distribution
3] Location determined by the mean
