Statistics Questions

[The Tripster]

I'm working in a team project and I hope some of you guys can help us out. I figure you guys would mostly likely know these answers. These are just multiple choice questions that lead into other stuff. Some of these questions we've argued about alot and really are unsure of the answers. Please provide some reasion behind it as it is just as important.

Which of the following is an example of performing statistical inference?
A. Calculate the mean number of fruit trees damaged by Mediterranean fruit flies in California last year.
B. Examine the weights of a sample of 10 candy bars to see if their average weight is 6 ounces.
C. Examine the weights of a sample of 25 manufacturer parts to see if the average weight of all the parts produced by the process is 3 pounds.
D. None of the above.

Which of the folling is NOT a mutally exlusive situation?
A. When event A and Event B can occur at the same time.
B. When event A and Event B can not occur at the same time.
C. A frequency distribution with classes 0-10 and 10-20, with open upper and lower limits.
D. A frequency distribution with classes 0-10 and 10-20, with open upper and closed lower limits.

Which of the folling is NOT a collectively exhaustive situation?
A. When event A and Event B can occur at the same time.
B. When event A and Event B can not occur at the same time.
C. A frequency distribution with classes 0-10 and 10-20, with open upper and lower limits.
D. A frequency distribution with classes 0-10 and 10-20, with open upper and closed lower limits.

Under which of the following conditions might stratified random sampling be appropriate?
A. The population can be divided into a large number of strat so that each stratum contains only a few individuals.
B. The populations can be divided into strata so that indivudlas in each stratum are as different as possible.
C. The populations can be divided into strata of equal sizes so that each individual still has the same chance of being selected.
D. The population can be divided into a small number of strata so that each stratum contains a large number of individuals.