Suppose that the daily number of errors a randomly-selected bank teller makes is denoted by X and follows the distribution given in the table below.? A human resource manager records the daily numbers of errors of two randomly selected tellers. Denote the associated random variables by X1 and X2. As the selection is random, X1 and X2 are independent and follow the same distribution as X. The manager then computes the sample mean
? where the sample size is n = 2. ??
x |
0 |
1 |
2 |
P(X = x) |
0.6 |
0.2 |
0.2 |
??????
- Find the mean and variance of X1. Explain why we do not need to find the mean and variance of X2 once we know those of X1.