Let X denote a random variable which corresponds to the number of players in a team who get injured during a game. If we assume that each player hasequal probability of being injured, which is 0.2 , and there are 10 of themparticipating in each game.

a. Is X a discrete or a continuous random variable?
b. What kind of distribution X follows?
c. Compute the probability that nobody or only one person will be injured in a game.
d. Write down the expression which gives the average value of X (also known as the expected value), what is the value of this expression?
e. Write down the expression that gives the variance of X (average squared distance from the mean ) what number is this expression equal to?
f. Assume that players can be ranked according to their performances and no two people are equally good. If two players get injured what is the probability of best player being one of them ? Note that all combinations of two people are equally likely to get injured.

(a)

The values of X can be 0, 1, 2 , ..., 10 . So, X is a discrete random variable.

(b)

The distribution of X is Binomial distribution with the parameters n = 10 and p = 0.2

(c)

Probability that no one or one person will be injured = P(X = 0) + P(X = 1)

= 10C0 * 0.20 * (1 - 0.2)10-0 + 10C1 * 0.21 * (1 - 0.2)10-1

= 0.810 + 10 * 0.2 * 0.89

= 0.3758096

(d)

Average value of X = np

Average value of X = 10 * 0.2 = 2

(e)

Variance of X = np(1-p)

Variance of X = 10 * 0.2 * (1 - 0.2) = 1.6

(f)

Number of ways in which 2 people gets injured = 10C2 = 10! / ((10-2)! 2!) = (10 * 9) / (2 * 1) = 45

Assume the best player got injures, number of ways in which one people out of remaining 9 people gets injured = 9C1

= 9! / ((9-1)! 1!)

= 9

Probability that the best player got injured = Number of ways in which 1 people gets out of 9 and best person gets injured / Number of ways in which 2 people gets injured

= 9 / 45

= 0.2

so a parallelogram is just like a square base times height. multiply 40 and 39 to get 1560 inches.

a triangle is base times height divided by two. so multiply 7.9 and 5 and then divide it by 2 to get 19.75inches.

the kite can be split into two separate triangles and added together to get the total area. 30 x 4 /2 which equals 60. make sure to double it for the two triangles making 120.

the answer is; biodiversity resulting from few ancestors

adaptive radiation occurs when a population is subjected to a large natural environment with spatial ecological variations. the parts of the population in the different ecologies begin to adapt to their local environments. due to non-random mating across the large populations, this causes the different populations from the large population to speciate within their local environments. they, therefore, diverge to different species sharing a common ancestor.