Rewrite given data in increasing order:
28, 61, 63, 65, 66, 67, 68, 69, 82, 86, 87
An outlier is an observation that lies an abnormal distance from other values in a random sample from a population. As you can see that number 28 lies an abnormal distance from other values.
Answer A: 28
The mean (or average) of a set of data values is the sum of all of the data values divided by the number of data values.
[tex]\text{mean with outlier}=\dfrac{28+61+63+65+66+67+68+69+82+86+87}{11}=\dfrac{742}{11}=67.454545...\approx67.45.[/tex]
Answer B: 67.45
[tex]\text{mean without outlier}=\dfrac{61+63+65+66+67+68+69+82+86+87}{11}=\dfrac{742}{10}=71.4.[/tex]
Answer C: 71.4
