How Close Is Close Enough

Question 9 asks students to use number sense to determine which estimates for Shape D might be questionable, i.e., which estimates might be worth disregarding. Students might decide that 75 sq cm or 97 sq cm seem to be unreasonable in comparison to the other pieces of data. The other estimates cluster within 5 sq cm of the median of 88 sq cm. Removing the outlier of 75 sq cm changes the median only slightly to 89 sq cm. If students decide to throw out 75 sq cm and 97 sq cm, the median of the remaining five pieces of data is 88 sq cm. Taking out the highest and lowest estimates does not significantly change the median.