# John

### Normal distribution finding variable c?

Assuming Z is a normal standard variable, how woudd I find c such that P(Z < c) = .15? and also c such that P(-c < Z < k) = .80

1 AnswerMathematics8 years ago### Coin flip probability?

If a fair coin is tossed repeatedly what is the probability that the (n-5)th head occurs on the nth toss?

2 AnswersMathematics8 years ago### Poisson approx stat question?

Suppose x is a binomial random variable with n = 100, p = 0.1. Find a) P(X >= 18) exactly, B) P(X>=18) using a Poisson approx

1 AnswerMathematics8 years ago### statistical suppose that random variable x takes on only the values 1 and 2, if E[x] = 1.25, what is Var(x)?

suppose that random variable x takes on only the values 1 and 2, if E[x] = 1.25, what is Var(x)?

2 AnswersMathematics8 years ago### Poker Probability Question?

An ordinary die is tossed until the first 5 occurs.

a. What is the probability that the die is tossed 3 times?

b. What is the probability that the die is tossed at least 3 times?

c. What is the probability that the die is tossed and odd number of times?

2 AnswersMathematics8 years ago### Probability Car not starting?

During the winter a man has trouble starting his two cars. The probability that car 1 starts is .8 and the probability that car 2 starts is .45. There is a probability of .35 that both cars starts.

a. What is the probability that at least one car starts

b. What is the probability that neither car starts

c. What is the probability that Car 1 starts but Car 2 does not?

d. What is the probability that exactly one car starts?

1 AnswerMathematics8 years ago### Marbles Probability Question?

Box 1: 2 red marbles, 4 white.

Box 2: 4 red, 2 white

Box 3: 6 red, 6 white

A die is tossed. Box 1 is picked if a "1" comes up, box 2 is picked if an even is picked, and otherwise it is box 3. Once a box has been picked, a marble is selected at random from that box. What is the probability that the marble is red?

2 AnswersMathematics8 years ago### Alphabet probability?

Five letters are selected from the alphabet one at a time with replacement to form a five letter 'word'.

What is the probability that the word consists of 5 different letters?

What is the probability that the word consists of only vowels if the letters are taken without replacement?

1 AnswerMathematics8 years ago### Probability question?

A toy manufacturer inspects boxes of toys before shipment. Each box contains 200 toys. The inspection procedure consists of randomly selecting 10 toys from the box. If more than 2 of these 10 toys are found to be defective, then the box is not shipped. Suppose that a given box has 5% defective toys. What is the probability that the box is shipped?

1 AnswerMathematics8 years ago