Consider the random variable, X, whose probabilities are given in this table.
X | P(X) |
0 | 0.2373 |
1 | 0.3955 |
2 | 0.2637 |
3 | 0.0879 |
4 | 0.0146 |
5 | 0.0010 |
What is the standard deviation of this probability distribution? Round to the nearest thousandth (three decimal places), if needed.
Solution:
x | P(x) | x * P(x) | x2 * P(x) |
0 | 0.2373 | 0 | 0 |
1 | 0.3955 | 0.3955 | 0.3955 |
2 | 0.2637 | 0.5274 | 1.0548 |
3 | 0.0879 | 0.2637 | 0.7911 |
4 | 0.0146 | 0.0584 | 0.2336 |
5 | 0.001 | 0.005 | 0.025 |
Sum | 1 | 1.25 | 2.5 |
Mean = X * P(X)
= 1.25
Standard deviation =
=X 2 * P(X) - 2
= 2.5 - (1.25)2 = 0.9375
Standard deviation = = 0.968
Get Answers For Free
Most questions answered within 1 hours.