Complete the probability distribution table. (Report probabilities accurate to 4 decimal places.) Find the mean of this probability distribution. (Appropriate rounding rules apply.)

Question

The Sky Ranch is a supplier of aircraft parts. Included in stock are 6 altimeters that are correctly calibrated and two that are not. Three altimeters are randomly selected without replacement. Let the random variable xxrepresent the number that are not correctly calibrated.

Complete the probability distribution table. (Report probabilities accurate to 4 decimal places.)

X P(x)

0
1
2
3

Find the mean of this probability distribution. (Appropriate rounding rules apply.) 

mean = 

Answer 1

If there are 6 altimeters that are correctly calibrated and two that are not, then there are 8 in total. Since three altimeters are randomly selected, we can assume the probability of any 1 being selected is equal (i.e.1/8).

We can use the classical method to compute the probability of x:P(x)=(numbers of ways choosing altimeter that is not correctly calibrated)/(number of possible outcomes)

Since we don't care about the order, we should use a combination to calculate the

number of way x=0, 1, 2, and 3 to fill in the table.

I'll let you do the calulations.