The following is a table of probabilties calculated from a survey of BHCC students with the question asked "How many classes are you taking this semester?

Question

The following is a table of probabilties calculated from a survey of BHCC students with the question asked "How many classes are you taking this semester?"

x: # of classes	1	2	3	4	5
P(x)	0.16	0.26	0.14	0.35	0.09

Using the table, find the following probabilities for a student selected at random:

a.) What is the probability that a student is taking 2 or more classes?   

b.) What is the probability that a student is taking at least 3 classes?   

c.) What is the probability that a student is taking more than 3 classes?   

d.) What is the probability that a student is taking less than 2 classes?   

e.) What is the probability that a student is taking no more than 2 classes?   

f.) What is the average (mean) amount of classes a student takes at BHCC? 5.12Incorrect  

Answer 1

Are you looking for someone to do your homework for you or are you looking to learn?

I will assume to learn so here are the learning points.

With a table of probabilities that is discrete you can determine probabilities of a discrete event happening : example P( x=3) = 14% or 0.14

You can also determine the probability of getting a result less than a value y (sum all the probabilities with x < y) .

You can determine less than or equal to a value y ( sum all the probabilities with x< y and add probability for x = Y)

This is the same as no more than y. ( sum all the probabilities with x< y and add probability for x = Y)

The same is true for greater than

P(x>y) is sum of all the probabilities with x>y

Also greater than or equal to

P(x>y) is sum of all the probabilities with x>y plus P(x=y)

this is the same as no less than y

With these rules you can answer questions a thru e.

For example, question e is really asking what is the probability that a student is taking either 1 or 2 classes this semester. The answer is of course .16 + .26 or .42

The last question (f) needs the definition for expected value because mean is in this case the same as expected value.

E(X) = ∑(x_i * P(x_i) ) for all i's ( i = 1 thru n where n is number of discrete probabilities or 5)

Just do the sum of all elements, by hand or with a spread-sheet. In this problem the second values in the summation for i=2 are x₂ = 2 P(x₂) = 0.26 so the product would be 0.52 Do this for all the values of x_i, sum them up, and that is the expected value.

check: your answer should be between 2.75 and 3.10

Remember, this is a learning forum, not a homework answering service. If you want more explanation as to how these notes work in regard to the classwork feel free to contact me for some tutoring @ www.wyzant.com/tutors/david4745