Question

The random variable X ~ B(5, 0.8). Find the following using a Ti-83/84
a. Mean
b. Standard Deviation
c. P(3)
d. P(x > 3)

Answer 1

The random variable X ~ B(5, 0.8).

n = sample size = 5

p = Probability = 0.8

a) Mean = n*p = 5*0.8 = 4

b) Standard deviation =

c)

We have to find P(3)

By using Ti-84 we have to find this probability.

Click on 2ND -------> VARS --------> binompdf( -------->

trials: 5

p: 0.8

x value: 3

Click on paste.

We get

P(3) = 0.2048

d)

Now we have to find P(X > 3)

P(X > 3) = 1 - P(X 2)

By using Ti-84 we have to find this probability.

Click on 2ND -------> VARS --------> binomcdf( -------->

trials: 5

p: 0.8

x value: 2

Click on paste.

We get

P(X > 3) = 1 - P(X 2) = 1 - 0.05792 = 0.9421

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