Unit sales for new product ABC have varied in the first seven months of this year as follows: Month Jan Feb Mar Apr May Jun Jul Unit Sales 148 329 491 167 228 285 441 What is the interquartile range (IQR) of the data? Please specify your answer as an integer. Note: Use the following formula to find quartile locations: Lq = (n+ 1) . where q is the quartile index (e.g., q=1 for the first quartile) and n is the number of data points. Excel's QUARTILE (and PERCENTILE) function uses a different method to compute quartile boundaries