What is the proper way to interpret a 95% confidence level (or the confidence interval procedure)?

Suppose two sections of the same class take the same exam and produce the results shown in the following histograms.  Which section had a higher standard deviation on the exam and why?

Male players at the high school, college, and professional ranks use regulation basketballs that weigh on average 22 ounces with a standard deviation of 1 ounce.  Assume that the weights of the basketballs are Normally distributed.  If a regulation basketball is randomly selected, what is the probability that it will weigh exactly 22.5 ounces?  Choose the best answer.

Which of the following scenarios should not use a paired t-test?

The objective of statistical inference is to:

Which of the following values can be a probability?

A student collected heights for a sample of 50 individuals.  He mistakenly recorded the tallest individual as 750 inches rather than 75 inches tall.  Which of the following statistics would be affected by this typo?

6). Ecology is the study of interactions between organisms and their nonliving environment. 

To convert molecules to moles, you would divide by ___.

 If the empirical formula of a compound is NO₂, which of the following could be its molecular formula?