Characteristics of a Bell Curve; probability calculations, sample confidence

1. Give at least 5 characteristics of the Bell Curve

2. For a normally distributed population, mean of 6.5 and standard
deviation of 4, compute:
a. The probability of picking one item from the population and having it fall between 6.5 and 14.5
b. The probability of picking one item and having it fall above 14.34
c. The point, if the probability of picking an item from the population and having it fall above the point is 2.5%
d. Two points, equidistant from the mean, one to the left of the mean and one to the right that will include 98.98% of the population

3. A sample of 300 is taken and the sample mean is computed to be 7.65 and the sample standard deviation is 5. Assume the data is ratio level.
Compute the 95% confidence interval on the mean.
Compute the 3.9% confidence interval on the mean

Which confidence interval is more practical and useful in a business situation? Why?

1. The total area under a probability distribution graph is equal to _____.
2. The normal distribution is a _____ distribution.
3. Discuss the shape of the normal curve.
4. Define "confidence level" in estimating mu, the population mean.

TRUE OR FALSE (With justification)?
If in a probability distribution you got the sum of probabilities less than one, it may mean that you skipped some possible outcome/outcomes.
Health insurance policies are set up in such a way that a healthy person has a negative expected value, and a sickly person has a positive one.

1. This week we learned about normal distributions:
a. Using your own words, tell me what the difference is between a normal distribution and a standard normal distribution.
b. Why do we convert values to z scores to find probability?
2. What is the difference between z scores and area in a bell curve?
3. T / F The n

What shape curve do you get when your data set has the mean, median, and mode all with the same value?
Could the value of the sample mean and the value of the population mean ever be the same?

Write a paragraph about the normal distribution. In the paragraph give an example of a distribution that you would judge to be nearly normal and explain why you have made that conclusion. Estimate the mean of this distribution and the standard deviation. Then estimate a probability based upon those values: (E.g., average height

The Sony corporation produces a Walkman that requires two AA Batteries. The mean life of these batteries in this product is 35.0 hours. The distribtion of the battery lives closely follows the normal probability distribtion with a standard deviation of 5.5 hours. As a part of their testing program Sony tests samples of 25 batter

Please help with the following problems.
1. For df = 25, determine the value of A that corresponds to each of the following probabilities:
a.P(t > A) = 0.25
b. P( < A) = 0.10
c. P(-A < t < A) = .99
2. Given the following observations in a simple random sample from a population that is approximately normally distrib

1. What shape would your distribution histogram be if the variable is approximately normally distributed?
2. True or False. As the amount of confidence increases, the required sample size should decrease. Explain your answer.