Variables and graphs
This variable is the one you change on purpose in an experiment.
Independent variable
The average of a set of numbers.
Mean
This describes the overall pattern or outline of the scatterplot.
Shape
A testable prediction about what you think will happen.
A testable prediction
This value tells you the strength and direction of a correlation.
r-value (correlation coefficient)
This variable responds to the changes made in the experiment.
Dependent variable
The middle value when data is arranged from lowest to highest.
Median
This describes whether the relationship goes up or down.
Direction (positive or negative)
A statement that says there is no relationship or no effect.
Null hypothesis (H₀)
An r-value of –1 means this type of correlation.
Perfect negative correlation
Which variable is placed on the x-axis of a graph?
Independent variable
The number that appears most frequently in a dataset.
Mode
This describes how close the data points are to a straight line.
Strength (how close points are to a line)
You do this to the null hypothesis when the p-value is below 0.05.
Reject the null hypothesis
An r-value of +1 means this type of correlation.
Perfect positive correlation
The variables that must be kept constant throughout the experiment.
Controlled variables
The formula for calculating mean.
Mean = (sum of all values) ÷ (number of values)
If data points form a perfect straight line, this is the type of correlation.
Perfect correlation
The value that tells you the probability your results happened by chance.
p-value
An r-value close to 0 indicates this.
No correlation / very weak correlation
Type of graph used for showing relationships between two continuous variables
Scatterplot
This measure tells you how spread out the data is from the average.
Standard deviation
On a scatterplot, this type of relationship occurs when one variable increases as the other decreases.
Negative relationship / negative correlation
When results are unlikely to have occurred randomly, they are described as this.
Statistically significant
When the r-value is negative, the direction of the relationship is this.
Negative direction (as one increases, the other decreases)