Four rotten oranges are accidentally mixed with 16 good ones. Three oranges are drawn at random from the mixed lot. Let X be the number of rotten oranges drawn. Find the mean and variance of X.
1. Assuming absence of stars in the vicinity, the only gravitational force exerted on astronaut is by the spaceship.
2. But this force is negligible.
3. Hence, once astronaut is out of...
Let X be the random variable defined as the number of red balls.
Then X = 0, 1
P(X = 0) = \(\frac{3}{4}\times\frac{2}{3}=\frac{6}{12}=\frac{1}{2}\)
P(X = 1) = \(\frac{1}{4}\times\frac{3}{3}+\frac{3}{4}\times\frac{1}{3}=\frac{6}{12}=\frac{1}{2}\)
Probability Distribution Table:
X
0
1
P(X)
\(\frac{1}{2}\)
\(\frac{1}{2}\)