Statistics and Probability Answers

two cards are drawn from a well shuffled pack of 52 cards and thrown away. find the probability of drawing an ace from the remaining 50 cards

First graders who misbehave in school may be more likely to be regular smokers as young adults according to a new study presented in the July 2004 issue of the American Journal of Epidemiology. After following a group of U.S. first graders for 15 years, it was found that among those kids who had tried smoking and misbehaved, 68% were daily smokers. (Give your answers correct to three decimal places.)
(a) What is the probability that exactly two of the next three randomly selected young adults who misbehaved in early grades and have tried smoking are daily smokers?

A group consists of 15 people: 5 Americans, 6 Canadians and 4 Mexicans.

(a) In how many ways can a sub-group of 4 people be selected?







(b) In how many ways can a sub-group of 4 people consist of all Canadians?







(c) What is the probability that a sub-group will consist of all Canadians?







(d) In how many ways can a sub-group of 4 people consist of 2 Canadians and 2 Mexicans?







(e) In how many ways can a sub-group of 4 consist of 1 American, 1 Mexican and 2 Canadians?

a lottery consists of 10000 tickets out of which 10 are prizes. if a person selects 2 tickets what is the probability of not getting a prize

Of every 4000 bolts produced in a factory , 800 ofbthem are faulty calculate the probability of a bolt chosen at random not being faulty

Suppose that a class contains 15 boys and 30 girls and that 10 students are to be selected at random for a special assignment. Find the probability that exactly 3 boys will be selected.

The variance of Bernoulli random variable is π(1-π) where π is the probability of a successful Bernoulli trial (i.e. probability that x = 1). Using the formula for the probability function (p.f.) of a Bernoulli random variable, and the formula for variance, prove that V(X) = π(1-π).

What practical applications does knowing the spread of a distribution have? When would a large/small spread be good or bad? Please give an example.

a green marble is placed in a bag with 99 other marbles of various colors. which of the following could never be in the probability that the green marble is randomly chosen from the bag, regardless of the color of the other 99 marbles?
A. 20%
B.0.7
C.3/4
D.2

In a community there are two families black and white. 10 families are selected to be interviewed about the school district.what is the probability of all families are white and probability of all 10 families are black? if all ten are selected as either all white or all black would you consider this a racial bias in the selection?