Let X be the number of packages being mailed by a randomly selected customer at a certain shipping facility. Suppose the distribution of X is as follows. x 1 2 3 4
p(x) 0.3 0.4 0.1 0.2
A) Consider a random sample of size n = 2 (two customers), and let Xbar be the sample mean number of packages shipped. Obtain the probability distribution of Xbar. B) Use (a) to calculate P (Xbar < = 2.5).C) If a random sample of size 4 is selected, what is P (Xbar <= 1.5)?
D) Find V(Xbar).

Asmall (but heavy) particle placed in a glass of water will follow a zigzag motion because the particle will bounce off of the water molecules it meets. this is called brownian motion. a physicist simulates this on a computer, by varying the distance a particle can travel (called the mean free length), on average, before it collides with a water molecule and assigning the change in motion to be one of 8 directions, each with a similar probability. by running the simulated particle (with the same mean free length) many times she determines that it should take 15 seconds, on average, for the particle to fall to the bottom, with a standard deviation of 1.5 seconds. next she lets a real particle fall through a glass of water and finds that it took 18 seconds. what does she conclude, and why?

In a sample of 200 residents of georgetown county, 120 reported they believed the county real estate taxes were too high. develop a 95 percent confidence interval for the proportion of residents who believe the tax rate is too high. (round your answers to 3 decimal places.) confidence interval for the proportion of residents is up to . would it be reasonable to conclude that the majority of the taxpayers feel that the taxes are too high?

The amount spent on food and drink by 20 customers is shown below what is the modal amount spent ?