Central Tendency

Question 1

Which measure of central tendency should I use?

Answer 1

Nominal - mode
Ordinal - Median
Interval/ration - mean or median (if highly skewed or have outliers).

Question 2

Key characteristics of graphs

Answer 2

(for interval and ratio units of measure)
- peaks (represents the mode)
- spread (represents variance)
- symmetry

Question 3

Kurtosis

Answer 3

The relative peaked-ness or flatness of the distribution. It reflects whether the scores are more or less evenly distributed throughout the measurement range.

Question 4

Platykurtic

Answer 4

When the scores are more evenly spread out. Greater proportion of the scores fall towards the tails.

Question 5

Leptokurtic

Answer 5

The scores are bunched together with steeply sloping sides

Question 6

Symmetrical

Answer 6

When the data frequencies decrease at equal rates above and below a central point.

Question 7

Positive Skew

Answer 7

Observations are bunched at the lower score values. Mode first, then median, then mean.

Question 8

Negative Skew

Answer 8

Observations are bunched at the higher score values. Mean first, then median, then mode.

Question 9

Bimodal data

Answer 9

distributions with two peaks, or modes, that may or may not be equal.