Question

100, 100, 99, 98, 92, 91, 91, 90, 88, 87, 87, 85, 85, 85, 80, 79, 76, 72, 67, 66, 45

 

d)           James obtained a mark of 90 and Petrus obtained a mark of 79 for the test. How would you describe their results in relation to the mean? 

Answer 1

d)

$$mean=\mu=E(X)=\dfrac{1}{21}(100+100+99+98$$

$$+92+91+91+90+88+87+87+85$$

$$+85+85+80+79+76+72+67+66+45)$$

$$=83.95$$

James obtained a mark of 90 which is greater than the mean mark among 21 students.

Petrus obtained a mark of 79 which is less than the mean mark among 21 students.