Explain how the interquartile range of a data set can be used to identify outliers.

26. How can you describe the spread of data using a box-and-whisker plot?

Explain how error measures can help to optimize moving averages, weighted moving averages, and exponential smoothing methods.

Some data sets include values so high or so low that they seem to stand apart from the rest of the data. These data are called outliers. Outliers may represent data collection errors, data entry errors, or simply valid but unusual data values. It is important to identify outliers in the data set and examine the outliers carefully to determine if they are in error. One way to detect outliers is to use a box-and-whisker plot. Data values that fall beyond the limits Lower limit: Q1 − 1.5 ✕ (IQR)Upper limit: Q3 + 1.5 ✕ (IQR) where IQR is the interquartile range, are suspected outliers. In the computer software package Minitab, values beyond these limits are plotted with asterisks (*). Students from a statistics class were asked to record their heights in inches. The heights (as recorded) were as follows. 65 72 68 64 60 55 73 71 52 63 61 74 69 67 74 50 4 75 67 62 66 80 64 65   (a) Find the value of the interquartile range (IQR).IQR =  (b) Multiply the IQR by 1.5 and find the lower…