Part 2

Question 1

Define “Mean”

Answer 1

The simple mean of a set measurements is the sum of the measurements divided by the number of observations.

Question 2

Define “Median”

Answer 2

The middle value of an ordered dataset.

Question 3

Define “Mode”

Answer 3

The most frequent measurement.

Question 4

What is the general equation to obtain quartiles from an ordered dataset?

Answer 4

Qi = [i(n + 1)/4] th item

Question 5

How many...
a) Quartiles
b) Deciles
c) Percentiles
...does a dataset have?

Answer 5

a) 3
b) 9
c) 99

Question 6

a) Define “deviation from the mean”.

b) Why is this not a good evaluation of dispersion?

Answer 6

a) The difference between each observation and the mean.

b) The total will always add up to 0.

Question 7

a) When can the Emprical Rule be used to measure dispersion?

b) Give the limits and the proven percentages of data that falls within those limits

Answer 7

a) When the distribution of a dataset is bell-shaped
b) u = mean, sd = standard deviation
u - sd to u + sd –> 68% of the data
u - 2sd to u + 2sd –> 95% of the data
u - 3sd to u + 3sd –> 99.7% of the data

Question 8

Define “Correlation”

Answer 8

A measurement that describes the strength of the relationship between two qualitative variables.

Question 9

Under what conditions can Pearson’s correlation be calculated?

Answer 9

• When X & Y are interval/ ratio.
• When there is a linear relationship between X & Y.
• When X and Y come from a bell-shaped distribution.

Question 10

Under what conditions can Spearman’s correlation be calculated?

Answer 10

• When X & Y are ordinal.
• The relationship between X & Y are monotonically increasing/decreasing.
• Observations don’t come from a bell-shaped distribution.

Question 11

Under what conditions can Chebyshev’s Rule be used to measure dispersion?

Answer 11

The shape of the distribution doesn’t matter.

Question 12

What are the three levels of kurtosis?

Answer 12

1) Platykurtic (k < 3)
2) Mesokurtic (k ~ 3)
3) Leptokurtic (k > 3)