The present takehome quizzes are very similar to problems you will see on the tests.
The written correspondence assignments tend to be more conceptual than computational.
x-bar (an overscored x) is the mean of a sample (the average weight of 20 students) mu (the lower case Grek letter) is the same as E[X], the mean of the population or the theoretical mean for a probability distribution function.
sigma (lower case Greek letter) is the standard deviation of the population or the theoretical value for a probability distribution function; s is an eastimate for sigma based on a sample (s^2 is the the unbiased estimator for sigma^2 from a sample of a population). (We divide by n-1 to get s because we do not know the true mean of the population and there is other sampling error.)
p-hat (p with a caret (^) circumflex above it) is the proportion in a sample (the
percentage of 248 Iowans interviewed who approve of Clinton)
p is the actual proportion in the population (All Iowans, all voters)
sigma sub x-bar is the standard deviation among all possible values for x-bar
(for the given sample size); sigma sub x-bar is sigma/SQRT(n)
sigma sub p-hat is the standard deviation among all possible values for p-hat (for the given sample size; sigma sub p-hat is SQRT(p(1-p)/n)
z sub alpha (z with a subscript of the Greek letter alpha) is the z-score
beyond which alpha remains in the tail. Hence z_.02 is 2.05
N.B.: You will often see z_(alpha/2), in which case (alpha/2) is the area in the tail beyond the specified z value; alpha is the area in both tails that far away.
(1-alpha) denotes the level of confidence in a confidence interval
alpha denotes the level of significance in a test of significance.
P (upper case) denotes the level of significance of an observation; this is essentially the same as alpha above.