In: Statistics and Probability
Find the mean, variance and standard deviation for the probability distribution given below. Give your answers to at least 4 decimal places. X -4 3 9 11 P(X) 0.599 0.131 0.214 0.056 A. Mean = B. Variance = C. Standard Deviation =
Solution:
x P(x) X P ( x ) X2 P ( x )
4 0.599 2.396 9.584
3 0.131 0.393 1.179
9 0.214 1.926 17.334
11 0.056 0.616 6.776
1 5.331 34.873
A )Mean = = x P (x )
= 5.331
Mean = =5.3310
B ) Variance = 2 = x2 P (x ) - ( )2
2 = 34.873 - ( 5.331 )2
2 = 34.876 - 28.420
2 = 6.456
Variance= 6.4560
C ) Standard deviation =
= x2 P (x ) - ( )2
= 34.873 - ( 5.331 )2
= 34.876 - 28.420
= 6.456
= 2.5409
The standard deviation = 2.5409