Answer
a) y | p(y)
25 | 0.8
100 | 0.15
300 | 0.05
E(y) = ∑ y . p(y)
E(y) = 25 × 0.8 + 100 × 0.15 + 300 × 0.05
E(y) = 50
average class size equal to E(y) = 50
b) y | p(y)
25 | 
100 | 
300 | 
E(y) = ∑ y . p(y)
E(y) = 25 × 0.4 + 100 × 0.3 + 300 × 0.3
E(y) = 130
average class size equal to E(y) = 130
c) Average Student in the class in a school = 50
Average student at the school has student = 130
Answer:
A
Step-by-step explanation:
b is the range
Answer:
1/20
Step-by-step explanation:
1/4 = 0.25
0.25 / 5 = 0.05
0.05 as a fraction = 5/100
simplified
5 / 5 = 1
100 / 5 = 20
1/20
38 meters long is the answer