Which is a better measure of central tendency? If meanandmediarareclose thenthemeanwillgivethecorrectimpression If meanandmediararenotclose thenthemedians a betterimpression If difference between mean and median are more than 10% than the median has a skewed distribution 10% rule - Involves calculating the difference between the mean and median and then finding 10% of that smaller value (whether it's mean or median) to see which value is greater, the difference or the 10% of that smaller value Measure of variability - Range, interquartile, variance, standard deviation Range= Max value - min value [Note: not a good way to find variability] Interquartile Range (IQR) - When the difference between the 75th and 25* percentiles arethesame It is the midspread 509% IQR= Q - Q. Variance - Accurate measure of variability. It is the expectation of the squared deviation of a random variable from its mean Coefficient of Variation - (Standard deviation/Mean) x 100 Standard Deviation - A measure of the amount of variation or dispersion of a set of values. * A lowstandard deviation = Values tend to be close to the mean of the set . High standard deviation =Values are spread out over a wider range Shapeof Distribution Mean median = Positive shape (right-skewed) Resistant statistics - Median and interquartile