According to an IRS study, it takes an average of 330 minutes for taxpayers...

18. According to an IRS study, it takes an average of 330 minutes for taxpayers to prepare, copy, and electronically file a 1040 tax form. A consumer watchdog agency selects a random sample of 40 taxpayers and finds the standard deviation of the time to prepare, copy, and electronically file form 1040 is 80 minutes.

a. What assumption or assumptions do you need to make about the shape of the population?
b. What is the standard error of the mean in this example?
c. What is the likelihood the sample mean is greater than 320 minutes?
d. What is the likelihood the sample mean is between 320 and 350 minutes?
e. What is the likelihood the sample mean is greater than 350 minutes?

The standard error of the mean:
A. is never larger than the standard deviation of the population
B. decreases as the sample size increases
C. measures the varability of the mean from sample to sample
D. All of the above

A random sample of size n is to be drawn from a population with a mean = 500 and sd = 100. What sample size would be necessary to ensure a standard error of 25? Sample sizes are whole numbers.
This is based on the formula for the standard error of the mean.

Question: Suppose N = 80000, n = 16000 and s = 50.
a. Compute the standard error of the samplemean using the finite population correction factor.
b. Repeat part a assuming n= 32000.
c. Repeat part a assuming n = 80000.
d. Compare parts a, b and c, and describe what happens to the standard error of the samplemean as n i

I am trying to calculate the maximum tolerable error given a sample size. I am given the standard deviation and I have been told that the mean is within 1 of the population mean. Without the actual mean, how can I calculate the maximum tolerable error?
I am using:
maximum allowable error = (z-value * standard deviation)/sq

What is the Central Limit Theorem? How large should the sample size be if the underlying distribution of the population values are:
a. Normally distributed (discuss).
b. Non-normally distributed. (discuss)
2. What is the difference, if any, between the standard deviation of the sampleand the standard error of the mean

I need an idea for an example of the following question:
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1. Obtain an estimated value and its standard error (either from data or by educated guess) for each of TWO situations important to your business interests. For each case, find a confidence interval and write a sentence interpreting it. Explain your r

Why is it important to know the standard deviation for a given sample? What do researchers learn about a normal distribution from knowledge of the standard deviation? A sample of n=20 has a mean of M = 40. If the standard deviation is s=5, would a score of X= 55 be considered an extreme value? Why or why not?
Can you please d

1. Briefly define each of the following:
a. Distribution of samplemeans
b. Expected value of M
c. Standard error of M
2. For a sample selected from a population with a mean of ยต=50 and a standard deviation of s= 10:
a. What is expected value of M and the standard error of M for a sample of n = 4 scores?
b. What is the

Use the confidence level andsample data to find a confidence interval for estimating the population mean m.
Test scores: n = 101, x-bar = 96.8, sigma = 8.3, 99 percent confidence