The document explains how to calculate the mean of a set of observations. It provides a specific example using the numbers 1, 4, 5, 7, and 8, resulting in a mean of 5. The calculation is reiterated for clarity.

1. Mean = (sum of the observations)/(Total no. of observations)
= (1+4+5+7+8)/5 = 5
Thus mean = 5
Solution
Mean = (sum of the observations)/(Total no. of observations)
= (1+4+5+7+8)/5 = 5
Thus mean = 5