A fruit stall weighs nine apples, in grams: 152, 160, 148, 171, 155, 1630, 158, 149 and 166…

Step 1. With the slip. The total is 2889 g, so the mean is $\dfrac{2889\ \text{g}}{9} = 321\ \text{g}$. Sorted, the masses are $148, 149, 152, 155, 158$, $160, 166, 171, 1630$, so the median is 158 g.

Step 2. After the correction. The total is $2889 - 1467 = 1422$ g, so the mean is $\dfrac{1422\ \text{g}}{9} = 158\ \text{g}$. The median is still the 5th value, 158 g.

What it shows. The mean was misled: 321 g is twice the mass of any real apple. The median did not move. With the slip, $Q_1 = 150.5$ g and $Q_3 = 168.5$ g, so the upper fence is $168.5 + 1.5 \times 18 = 195.5$ g. The rule flags 1630 g as an outlier, and a look at it shows a slip.