Review: mode, medium and mean are good descriptive measures but only mean is used for statistical analysis.
Calculate standard deviation take the mean. Minus all data points by the mean. Square and sum your answers. Divide this answer by (n-1). Now you have the variance. To get the standard deviation take the square root of the variance.
Calculate standard error divide the standard deviation by the square root of n.
Calculate a 95 % confidence interval . 95% = 1.96 standard deviations. Multiply the standard error by this number. The 95% confidence interval range is the mean plus and minus this number.
If the mean is greater than the medium than the data is skewed left. And vise versa.
No comments:
Post a Comment