Question

During the 2013 regular NBA season, DeAndre Jordan of the Los Angeles Clippers had the highest field goal completion rate in the league. DeAndre scored with 61.3% of his shots. Suppose you choose a random sample of 80 shots made by DeAndre during the 2013 season. Let X = the number of shots that scored points

Answer 1

Answer:

a) The probability mass function for the Binomial distribution is given as:  

$P(X)=(nCx)(p)^x (1-p)^{n-x}$  

Where (nCx) means combinatory and it's given by this formula:  

$nCx=\frac{n!}{(n-x)! x!}$  

Let X the random variable of interest, on this case we know that:

$X \sim Binom(n=80, p=0.613)$

b) $\mu = n*p = 80*0.613= 49.04$

$\sigma = \sqrt{np(1-p)}= \sqrt{80*0.613*(1-0.613)}= 4.356$

c) For this case we can use the following excel code:

"=BINOM.DIST(60,80,0.613,FALSE)"

And we got 0.00355

d) $P(X>50) 1-P(X \leq 50)$

And we can use the following excel code:

"=1-BINOM.DIST(50,80,0.613,TRUE)"

And we got 0.3718

Step-by-step explanation:

Assuming the following questions:

a) What is the probability distirbution for X?

The binomial distribution is a "DISCRETE probability distribution that summarizes the probability that a value will take one of two independent values under a given set of parameters. The assumptions for the binomial distribution are that there is only one outcome for each trial, each trial has the same probability of success, and each trial is mutually exclusive, or independent of each other".

The probability mass function for the Binomial distribution is given as:  

$P(X)=(nCx)(p)^x (1-p)^{n-x}$  

Where (nCx) means combinatory and it's given by this formula:  

$nCx=\frac{n!}{(n-x)! x!}$  

Let X the random variable of interest, on this case we know that:

$X \sim Binom(n=80, p=0.613)$

b) Using formula calculate the mean and standard deviation of X

By properties we have:

$\mu = n*p = 80*0.613= 49.04$

$\sigma = \sqrt{np(1-p)}= \sqrt{80*0.613*(1-0.613)}= 4.356$

c) Use your calculator to find the probability that DeAndre scored with 60 of these shots

For this case we can use the following excel code:

"=BINOM.DIST(60,80,0.613,FALSE)"

And we got 0.00355

d) Find the probability that DeAndre scores with more than 50 of these shots

We want this probability:

$P(X>50) 1-P(X \leq 50)$

And we can use the following excel code:

"=1-BINOM.DIST(50,80,0.613,TRUE)"

And we got 0.3718