Probaility & Statistics

Problem: If Z is the standard normal random variable and Pr(-z < Z < z) = 0.6578, then z is? a. 1.00 b. 0.45 c. 0.95 d. 0.40 e. None of the above

Probability & Statistics

Problem 4. Let X denote the number of boys in a family with four children. Pr(X > 3) is? a. 5/16 b. ¼ c. 11/16 d. 2/3 e. None of the above

Probability and Statistics

Your score on three tests are 76,88, and 72. Your grade on the final exam will count twice as much as any one test grade in determining your average grade for the course. in order for your average grade for the course to be 82, your grade on the final exam must be: a. 85 b. 87 c. 77 d. 92

Solution pleas

1. There are 3 boxes. Each box contains several envelopes. Some envelopes have "you lose" written on them. The rest say "you win…" . However, of the ones that say "you win…" , some contain only a piece of paper saying "… nothing" . Each of the other contains a $5 bill. The first box contains 3 "lose" envelopes and 2 so-called "win" envelopes. The second contains 1 "lose" envelope and 3 "win "envelopes. The third box contains 2 "lose" envelopes and 2 "win" envelopes. Each box contains only one $5 bill(in an envelope marked" you win…"). Addie, who is blindfolded, selects a box at random and draws one envelope from the box. The envelope contains a $5 bill. What is the probability that Add... click for more

Solution please

2. Sally is at her house, and is going to toss a coin repeatedly. You are talking to Sally on the phone. After each toss of the coin, she will tell you (truthfully) whether the coin came up heads or tails. You know that Sally has a trick 2-headed coin, but you don't know whether she is going to toss that trick coin or an ordinary coin. You do know that it will be the same coin tossed each time. How many times in a row would Sally have to toss Heads in order for you to be at least 99% sure that she's tossing the 2- headed coin? (Note: being at least 99% sure that it is the 2-headed coin means having no more than a 1% chance of getting this result with a fair coin)