Answer:
The percentage of people that scored less than Calvin is 38.21 %
Step-by-step explanation:
In this question, we are concerned with calculating the percentage of exam scores lesser than what Calvin scores.
To calculate this, we first need to calculate the standard score or the z-score of Calvin result.
Mathematically;
z = (x - mean)/SD
from the question, x = 78, mean = 81 and SD = 10
Substituting this, we have
z = (78 -81)/10 = -3/10 = -0.3
So we proceed to calculate the probability.
P(x < 78) or P(z < -0.3)
We make use of the standard table to get this probability
P(z< - 0.3) = 0.38209
In percentage, this is same as 38.209% or more simply 38.21%
