Question

activities 0 1 2 3    4 5 6 7

probability 0.058 0.121 0.161 0.178 0.217 0.128 0.084 0.053

a) the mean is _______

b) the variance is ____________

c) the standard deviation is_____________

 

Answer 1

Solution:

We have to find mean , variance and standard deviation.

Formula:

where

Thus we need to make following table:

x: activities	P(x) Probability	x*P(x)	x2 *P(x)
0	0.058	0	0
1	0.121	0.121	0.121
2	0.161	0.322	0.644
3	0.178	0.534	1.602
4	0.217	0.868	3.472
5	0.128	0.64	3.2
6	0.084	0.504	3.024
7	0.053	0.371	2.597

Part a) Mean:

Part b) Variance:

where

thus

Part c) Standard Deviation: