Probability distribution calculator
Give the values of a random variable X and their probabilities - with an unknown like k if the question has one - and get k, the mean, the variance and the standard deviation with the working table ISC Mathematics expects.
Answer
- Mean E(X)
- 1
- E(X²)
- 3/2
- Variance
- 1/2
- Standard deviation
- 0.7071
Working
| x | P(x) | x·P(x) | x²·P(x) | F(x) = P(X ≤ x) |
|---|---|---|---|---|
| 0 | 1/4 | 0 | 0 | 1/4 |
| 1 | 1/2 | 1/2 | 1/2 | 3/4 |
| 2 | 1/4 | 1/2 | 1 | 1 |
- Mean = Σ x·P(x) = 1
- Variance = Σ x²·P(x) - (mean)² = 3/2 - (1)² = 1/2
- Standard deviation = √variance = 0.7071
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