Describing Data

Question 1

Which measure of central tendency is least bistable for normally distributed data?

Answer 1

The mean.

Question 2

Which measure of central tendency is least bistable for non-normally distributed data?

Answer 2

The median.

Question 3

What does a probability distribution allow that a frequency one does not?

Answer 3

Comparisons irrespective of sample size.

Question 4

Give 2 advantages of frequency plots.

Answer 4

They display all data points making no assumptions and they show potential outliers/odd ball values in context.

Question 5

Give 2 disadvantages of frequency plots.

Answer 5

Not very good as summaries and often have so many distributions that comparisons are difficult.

Question 6

Give 3 advantages of box plots.

Answer 6

They make very few assumptions, highlight potential outliers/odd ball values and facilitate comparisons between conditions.

Question 7

Give 2 disadvantages of box plots.

Answer 7

Plotting outliers can lead to a cluttered figure and a focus on them rather than the overall pattern of results.

Question 8

Give a formal definition of statistics.

Answer 8

A function of a sample where the function itself does not depend on the sample.”

Question 9

Briefly describe the Bayesian approach.

Answer 9

Uses subjective probability and asks about the likelihood of a view given the data.

Question 10

Briefly describe the frequentist approach.

Answer 10

Uses objective probability and asks about the likelihood of the data given a view of how the world works.

Question 11

How do we decide to reject a hypothesis, when any result is possible, but some are very unlikely?

Answer 11

Make an a priori decision as to what results are too unlikely.