1. ## String of questions...

1)Suppose a simple random sample of size n = 38 is obtained from a population of (I Believe it is called "Mu" its like a u) = 66 and (lower case sigma) = 19

a) Assuming the normal model can be used, describe the sampling distribution x-bar.
b) P(x-bar < 69.9)
c) P(x-bar (greater than or equal to) 67.6))

2) Suppose a geyser has a mean time between eruptions of 70 minutes. If the interval of time between the reuptions is normally distributed with standard deviation 22 minutes.

a) What is the probability that a randomly selected time interval between reuptions is longer than 80 minutes?
b) What is the probability that a random sample of 8 time intervals between reuptions has a mean longer than 80 minutes?
c) What is the probability that a random sample of 31 time intervals between reuptions has a mean longer than 80 minutes?
d) what effect does increasing the sample size have on the probability?
e) What might you conclude if a random sample of 31 time intervals between eruptions has a mean longer than 80 minutes?

3) Describe the sampling distribution of (^ below it is p). Assume the size of the population is 20,000.

a) Determine the mean of the sampling distribution (^ below it is p).
Mean(^ below it is p) =
b) Determine the standard deviation of the sampling distribution of (^ below it is p)
Standard Deviation(^ below it is p) =

4) Suppose a simple random sample of size n = 1000 is obtained from a population whose size is N = 1,500,000 and whose population proportion with a specified characteristic is p = .76.

a) Describe the sampling distribution of (^ below it is p)
b) What is the probability of obtaining x=780 or more individuals with the characteristic?
P(x (greater than or equal to) 780)) =
c) What is the probability of obtaining x=730 or fewer individuals with the characteristic?
P(x (less than or equal to) 730)) =

2. simple statistics of the first year in the department of statistics. check here: http:statlink.tripod.com and go to statistical theroy section

3. I'm pretty confused on where to look at this site.

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