Follow the table below to find the mean, variance and standard deviation for the random variable (answer to 4 decimal places). Mean: Variance: Standard deviation: Q2.3. A bag contains 4 red, 7 blue and 5 black balls. We consecutively pick two balls at random from the bag (without replacement).(i) Draw probability tree diagram, and (ii) find the probability we pick one red and one black balls? (answer to 4 decimal places) Tree diagram: (ii) Probability:
x P(X)
6 0.1
8 0.1
11 0.3
13 0.3
16 0.2