answer letter D for me In a certain population of the freshw

answer letter D for me

In a certain population of the freshwater sculpin. Cottus rotheus. the distribution of the number of tail vertebrate is as shown in the table. Find the probability that the number of tail vertebrate in a fish randomly chosen from the population is Find the expected value and standard deviation

Solution

d) If X denotes the number of Vertbrates, the table can be written as

Now by defnition expected value is sum (XP(X)) =21.49

and variance is =462.25-(21.49)^2=0.4299

X	P(X)	XP(x)	X^2P(X)
20	0.03	0.6	12
21	0.51	10.71	224.91
22	0.4	8.8	193.6
23	0.06	1.38	31.74
Total	1	21.49	462.25