Detecting unusual numbers or outliers in a data set is important in many disciplines, because the outliers identify interesting phenomena, extreme events, or invalid experimental results. a simple method to check if a data value is an outlier is to see if the value is a significant number of standard deviations away from the mean of the data set. for example, is an outlier if

where is the data set mean, is the data set standard deviation, and is the number of standard deviations deemed significant.

assign outlierdata with all values in userdata that are numberstddevs standard deviations from userdata's mean. hint: use logical indexing to return the outlier data values.

ex: if userdata is [9, 50, 51, 49, 100 ] and numberstddevs is 1, then outlierdata is [9, 100].