M4U8D1 Correlation and Scatterplots

Front

What is correlation in statistics?

Back

Correlation is a statistical measure that describes the extent to which two variables change together. A positive correlation means that as one variable increases, the other also increases, while a negative correlation means that as one variable increases, the other decreases.

Front

What does a scatterplot represent?

Back

A scatterplot is a graphical representation of two variables, where each point represents an observation. It helps to visualize the relationship between the variables.

Front

What does a positive correlation look like on a scatterplot?

Back

In a scatterplot with a positive correlation, the points tend to rise from left to right, indicating that as one variable increases, the other variable also increases.

Front

What does a negative correlation look like on a scatterplot?

Back

In a scatterplot with a negative correlation, the points tend to fall from left to right, indicating that as one variable increases, the other variable decreases.

Front

What does it mean if there is no correlation between two variables?

Back

If there is no correlation, the scatterplot will show points that are randomly distributed, indicating that there is no predictable relationship between the two variables.

Front

How can you predict the next point in a scatterplot?

Back

To predict the next point in a scatterplot, observe the trend of the existing points and extrapolate based on the established pattern.

Front

What is the range of correlation coefficients?

Back

The correlation coefficient ranges from -1 to +1. A value of +1 indicates a perfect positive correlation, -1 indicates a perfect negative correlation, and 0 indicates no correlation.

Front

What is the formula for calculating the correlation coefficient (r)?

Back

The formula for the Pearson correlation coefficient (r) is: r = (nΣxy - ΣxΣy) / sqrt[(nΣx^2 - (Σx)^2)(nΣy^2 - (Σy)^2)], where n is the number of pairs, Σxy is the sum of the product of paired scores, Σx is the sum of x scores, and Σy is the sum of y scores.

Front

What is a trend line in a scatterplot?

Back

A trend line is a straight line that best represents the data on a scatterplot. It can be used to predict future values based on the existing data.

Front

What is the difference between correlation and causation?

Back

Correlation indicates a relationship between two variables, but it does not imply that one variable causes the other to change. Causation means that one variable directly affects another.