a. Gender, measured male or female. (It measures a non-numerical variable and truly measures that feature.
b. Time, measured on a clock that is always 5 minutes fast. Everyone would get the same reading so it is reliable, but it would be consistently off by 5 minutes, so it is biased.
c. Weight on a postal scale that sometimes measures too high and sometimes measures too low, with equal likelihood. It is unbiased since there is no systematic bias in one direction, but unreliable because different people measuring the same package would get different answers.
Problem 10.
They are not likely to be a valid measure, because many crimes (like rape or domestic violence) go unreported. They are a reliable measure, because we would all agree on how to get the same answer, namely, just look at what is in the records of reported crimes.
Problem 12.
a. Closed-form question, 4 choices of response were given.
b. There is only one choice of aspirin, namely Brand B. Further, those who prefer Tylenol would have to choose between plain Tylenol or Extra-Strength Tylenol, thus splitting the vote.
c. The claim is very misleading and biased in favor of Brand B aspirin. Anyone who prefers aspirin at all would have to choose Brand B aspirin. Further, those who prefer Tylenol had their votes split into two groups. Perhaps the number who prefer Tylenol in general is higher than the number who prefer aspirin in general, but the Tylenol vote is split while the aspirin vote all goes to Brand B.
Problem 15.
The order of the questions most likely influenced the answer to the second one. Since the majority of the respondents first acknowledged thinking most presidents have had extramarital affairs, they were not is a position to describe Clinton's faults as worse than most presidents, when the alleged fault of his was an extramarital affair. Note the allegations of perjury and other offenses arose after this poll was taken.
Problem 21.
It is not completely valid, because people may interpret "on time" to mean "by the scheduled time" and not 15 minutes later. It is reliable, because everyone using that definition would agree on whether or not the flight made it on time.