stat 2300 3.1-.2

symmetry or skewness, peaks, clusters or gaps, outliers

unusually high or low observations

a typical or representative data value, mean/median

clustered together or spread out, range, variance, standard deviation, and interquartile range

xbar = sigma x / n (average)

sample mean

population mean

the middle score in a distribution; half the scores are above it and half are below it (M) if odd then middle data, if even the average two middle values, sometimes better to use median if outliers

if extreme values (very large or small) relative to the data do not affect its value substantially (median is)

the most frequently occurring score(s) in a distribution (if skewed may not be in middle) good for categorical data

mean > median

mean < median

mean = median , mean is preferred

If highly skewed use the median

the difference between the highest and lowest scores in a distribution, greatly changed by outliers, doesn't take into account other values

typical value for how far the data fall from their mean

sample variance

sample standard deviation

population standard deviation

population variance

68%, 95%, 99.7%