Statistics 1

• PMCC stands for product moment correlation coefficient
• R and Rs values range from -1 to 1
• The two conditions for pmcc is that the relationship between the two variables must be linear and that the values/information have to be normally distributed
• The two conditions for Spearman's Rank is that the relationship between the variables must be non-linear, and they have to be ranked before they are correlated.
• Bivariate data means data with two variables.
• Correlation gives the strength and direction of the relationship between the two variables.
• Correlation does not imply causation
• The word 'interpret' means to explain in context of the question
• When talking about Spearman's Rank, we talk about the variables having an association rather than correlation between each other
• The independent variable is the one that is being changed or controlled by the data collector and is called the explanatory variable
• The dependent variable is the one that is being recorded by the data collector and is known as the response variable.
• Properties of the regression line is that the sum of the residuals is 0 and the sum of the squares of the residuals is as small as possible
• a in the regression line represents the y-intercept and the b represents the gradient
• When interpreting the y-intercept, we say' when (x-variable) is 0, the expected (y-variable) would be (a)'
• When interpreting the gradient, we say 'For every 1 (x-unit) increase in the (x-variable), the (y-variable)increases/decreases by (b)(y-unit)
• When making predictions from a regression line, you can only predict y values from given x values because y is the dependent variable and depends on x
• interpolation is making predictions using values from the range of data and is labelled as reliable, extrapolation is making predictions using values from outside of the data range and is labelled as unreliable