Complete question:
A project is graded on a scale of 1 to 5. If the random variable, X, is the project grade, what is the mean of the probability
distribution below?
Grade(X)_____ 1_____2_____3_____4_____5
Frequency____3 _____5____ 9 ____ 5 ____ 3
P(X) : _______ 0.1 ___0.2 ___0.4 ___ 0.2 __0.1
Answer:
3
Explanation:
Given the probability distribution :
Grade(X)_____ 1_____2_____3_____4_____5
Frequency____3 _____5____ 9 ____ 5 ____ 3
P(X) : _______ 0.1 ___0.2 ___0.4 ___ 0.2 __0.1
The mean of the distribution :
Σ(X * P(X)) :
(1*0. 1) + (2 * 0.2) + (3 * 0.4) + (4 * 0.2) + (5 * 0.1)
0.1 + 0.4 + 1.2 + 0.8 + 0.5
= 3