Contemporary Math Class Problems
Chapter 16
1. 150 students in a math class take the final exam. The scores on the exam have an approximately normal
distribution with mean μ = 65 and standard deviation σ = 10.
The third quartile of the scores on the exam is approximately:
Q3 = μ + (.675) σ
Q3 = 65 + (.675)(10)
Q3 = 65 + 6.75
Q3 = 71.75, which rounds to 72
2. For a population of 2000 students taking the SAT math exam, the scores on the exam have an
approximately normal distribution with mean μ = 590 and standard deviation σ = 70.
The third quartile of the scores on the exam is approximately:
Q3 = μ + (.675) σ
Q3 = 590 + (.675)(70)
Q3 = 590 + 47.25
Q3 = 637.25, which rounds to 637
3. As part of a study on the metabolism of athletes, 400 college basketball players are randomly chosen
and their weights taken. The distribution of the weights is approximately normal. The average weight is
215 pounds and the standard deviation is 15 pounds.
A weight of 260 pounds corresponds to a standardized value of:
μ =215 σ=15 x=260
Z=(x – μ)/ σ
Z=(260 – 215)/15
Z=45/15
Z=3
A weight of 188 pounds corresponds to a standardized value of
μ =215 σ=15 x=188
Z=(x – μ)/ σ
Z=(188– 215)/15
Z=‐27/15
Z=‐1.8