Correlation
Measure correlation in Grade 10 statistics. Calculate and interpret the correlation coefficient r to assess strength and direction of linear relationships between two variables.
Key Concepts
Property A measure of the strength and direction of the relationship between two variables or data sets is called correlation. A relationship can have a positive correlation (points rise), a negative correlation (points fall), or no correlation (points are scattered).
As the hours you study increase, your test scores tend to increase. This is a positive correlation. The more you play a video game, the less battery life your controller has. This is a negative correlation. The number of hats someone owns has no relationship to their height. This shows no correlation.
Correlation is like checking if two things are buddies. When one variable changes, does the other change in a predictable way? If they both increase, they're positive pals. If one goes up while the other goes down, they're negative nemeses. If there's no pattern at all, they have no relationship.
Common Questions
What is correlation in statistics?
Correlation measures the strength and direction of the linear relationship between two variables. The correlation coefficient r ranges from -1 (perfect negative) to +1 (perfect positive), with 0 indicating no linear correlation.
How do you interpret different values of the correlation coefficient?
|r| near 1 indicates a strong linear relationship. |r| near 0.5 indicates moderate correlation. |r| near 0 indicates weak or no linear correlation. Positive r means as x increases, y increases.
What is the difference between correlation and causation?
Correlation shows a statistical relationship but does not prove one variable causes the other. A third variable or coincidence could explain the pattern. Always interpret correlation cautiously in context.