Quiz Tute 4

The skewness of a distribution refers to its:

• Flatness

• Peakedness

• Symmetry

• Central Tendency

• Variability

A positively skewed distribution has the greatest portion of its scores:

• Above the median

• Above the mean

• Between the 50th and 90th percentile

• Below the median

• Below the mean

A distribution of scores has a mean of 12, a mode of 18, and a median of 16. The distribution is:

• normal

• positively skewed

• negatively skewed

• rectangular

• U-shaped

One of the reasons the mean is the preferred measure of central tendency is because:

• a. it’s easy to calculate

• b. sometimes there isn’t a median

• c. it is the basis of many subsequent calculations, like variance and standard deviation

• d. it is always a good measure of central tendency

• a. a, b, c & d

The variance is:

• a. the average distance of scores from the mean

• b. the standard distance of scores from the mean

• c. the largest deviation of a score from the mean

• d. the average squared distance of scores from the mean

• e. the smallest deviation of the scores from the mean

Which of the following does NOT apply to the standard deviation?

• a. it is a measure of variability

• b. it is an intuitive description of a sample’s variability

• c. it is a measure of the amount by which scores deviate from the median

• d. it is square root of the variance

• e. it is a measure of the amount by which scores deviate from the mean

Calculate the average distance of the following scores from their mean:

2 3 4 1 2 3 4 1 5 5 6 2 3 2 4 5 6 2 2 1 3 3 4 5 6 7 7 8 5 4 3 3 2 3 4

• a. 0

• b. 0.5

• c. 1

• d. 1.5

• e. 2

What is the median of the following data set?

21 23 23 23 24 25 26 27 29 30 38 44 52

• a. 31

• b. 26

• c. 23

• d. 25

• e. 25.5

What is the most appropriate measure of central tendency for the following data set, and why?

21 23 23 23 24 25 26 27 29 30 38 44 82 110

• a.the mode, because it is easy to calculate

• b. the mean because it is the best measure of central tendency

• c. the mean because it is an unbiased statistic

• d. the median because the data set is negatively skewed

• e. the median because the data set is positively skewed

The tutors decide to all grade the same assignment, chosen at random. If they all give it a similar grade, we can say that the marking criteria has:

• a. good test-retest reliability

• b. good inter-rater reliability

• c. good construct validity

• d. good internal validity

• e. poor construct validity