Stats Help for College-level Students

e-value(expectation) and standard deviation of a distribution

Billy is collecting bottle caps from his favorite brand of soda pop. The company that produces it runs a contest: each bottle cap shows a picture of one of the 50 states of the United States, with each state equally likely. If you collect all 50 states, then you win a cash prize. 1. Find the e-value of your distribution of th ...continues

Joint Distributions (normal distributions)

Tim has two more problems to solve on his test, but he doesn't know how long it will take to finish them. He assigns mutually irrelevant normal distributions to the times, assigning a mean of 35 minutes to the first problem and 30 minutes to the second problem. He assigns a 95% chance that the first problem will take 35+-15 minu ...continues

Joint Distributions or uniform distributions : Working with probability and the roots of an equation.

You assign uniform distributions to a, b, and c (each between 0 and 1). What is your probability that all the roots of the following equation are real? So, if you used the quadratic formula to solve the equation and you got the square root of a negative number as a root then the roots would not be real. ax^2 + bx + c = 0

Distributions

A rare disease has just broken out. Doctor Johnson is trying to help, but while treating patients he might expose himself to the disease. He takes many precautions, but he doesn't know how much he's been exposed. Let the number x represent Doctor Johnson's exposure level. He doesn't know it for sure, but he assigns a uniform ...continues

Investment problem: mean, variance, etc.

Calculating the mean and variance for different portfolios. See attached file.

Distributions

A rare disease has just broken out. Doctor Johnson is trying to help, but while treating patients he might expose himself to the disease. He takes many precautions, but he doesn't know how much he's been exposed. Let the number x represent Doctor Johnson's exposure level. He doesn't know it for sure, but he assigns a uniform dis ...continues

Statistic Problem

The New York Stock Exchange (NYSE) consists of listing of approximately 1,500 companies, which offer shares of company stock to the public. Stockbrokers are interested not only in the individual stocks, but also in general trends established by the market as a whole. They often base inferences upon the daily closing prices of ...continues

Expected value

Calculate the e-time that an arriving pedestrian must wait until crossing. See attachment.

central limit theorem

PVC pipe is manufactured with a mean diameter of 1.01 inches and a standard deviation of 0.003 inches. What is the probability that a random sample of 9 sections of pipe will have a sample mean diameter between 1.009 inches and 1.012 inches? Assume the central limit theorem holds.

Probability

X follows a normal distribution with mean 20 and standrad deviation 4. Find b such that Prob(-b<=X-20<=b)=0.95