In: Statistics and Probability
1. A statistics professor classifies his students according to their grade point average (GPA) and their class rank. GPA is on a 0.0 – 4.0 scale, and class rank is defined as the lower class (year 1 and year 2) and the upper class (year 3 and year 4). One student is selected at random.
GPA | ||||
Under 20 | 2.0 -3.0 | over 3.0 | ||
Lower Class (Year 1 and 2) | 0.05 | 0.20 | 0.10 | 0.35 |
Upper Class (Year 3 and 4) | 0.10 | 0.35 | 0.20 | 0.65 |
0.15 | 0.55 | 0.30 | 1 |
a. Given that the student selected is in the upper class (year 3 and 4), what is the probability that her GPA over 3.0?
b. What is the probability that the student is in the upper class (year 3 and 4) or having a GPA over 3.0?
c. Are being in the upper class (year 3 and 4) and having a GPA over 3.0 independent? Prove statistically.
d. Are being in the upper class (year 3 and 4) and having a GPA over 3.0 mutually exclusive? Prove statistically.