About This Set
Each of these 25 questions needs one formula and one careful step: the mean, median or mode of a short list or a small frequency table, the empirical relation between the three, and the range or standard deviation of a few values. At this level most marks are lost before any calculation starts: the middle value is read before the list has been arranged, the highest frequency is written down as the mode instead of the value that has it, or the variance is given when the question asked for the standard deviation. Set a 25-minute timer, a minute a question as in Tier 2. With 21 or more right, go on to Practice Set 2; with fewer, look first for a list that was not arranged or a frequency written down as the mode.