Chapter 3: Central Tendency and Variability

Answers for all ‘Test Yourself’ questions from the book to check your performance and widen your overall understanding of the contents.

  1. This data is positively skewed; the tail leads off to the right.
  2. a)  Negatively skewed
    b) 21
    c) 4
    d) 3
  3. This could be pronounced in many ways.  You might have picked any one of these, but they are all correct: “z is a deviation divided by the sample standard deviation” or “z is the difference between a score and the sample mean, divided by the sample standard deviation” or “z equals x minus x bar, all over s”.
  4. a) Ratio, Mean
    b) Nominal, Mode
    c) Ordinal, Median
  5. a) 5
    b) 5
    c) 6.67
    d) 2.58
  6. There are many ways to do this, but here are some possibilities:
    “The centre of this dataset is 3.”
    “The distance between the highest and lowest value is 20”