Lv 125 points

# John

Questions9
• ### 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

• ### 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?

• ### 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

• ### 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)?

• ### 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?

• ### 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?

• ### 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?

• ### 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?