8.3 Mean, Median and Mode
Suppose we have a set of data with values, ordered from smallest to largest. If is odd, then the median is the data value at position . If is even, then we find the values at positions and . If those values are named and , then the median is defined to be .
8.4 Range and Standard Deviation
Here, s is the standard deviation, represents each data value, is the mean of the data values, is the number of data values, and the capital sigma () indicates that we take a sum.
8.6 The Normal Distribution
If is a member of a normally distributed dataset with mean and standard deviation , then the standardized score for is
If you know a -score but not the original data value , you can find it by solving the previous equation for :
8.8 Scatter Plots, Correlation, and Regression Lines
If a line has slope and passes through a point , then the point-slope form of the equation of the line is:
Suppose and are explanatory and response datasets that have a linear relationship. If their means are and respectively, their standard deviations are and respectively, and their correlation coefficient is , then the equation of the regression line is: