when to use mean median standard deviation and iqr
1) A manufacturer representing the spread of the lifetimes of bulbs from his production line. The standard deviation is 15.9 hours and the interquartile range is 27.7 hours. 2) Whether a businessman should use the median and IQR or the mean and standard deviation to compare the daily sales for this year with last year's. I really need to understand WHY so please give a reason for your choice. Thanks :)