Lecture 3 REVISED

Question 1

what does measures of central tendency and measures of variability focus on?

Answer 1

measures of central tendency focuses on the average or middle values

measures of variability focuses on the dispersion of data

Question 2

measures of central tendency

Answer 2

describes the centre position of a distribution for a dataset

e.g., mean, median, mode

Question 3

measures of variability

Answer 3

aid in analysing how dispersed a data distribution is

e.g., mean is 65/100, but data points can be at both 1 and 100

Question 4

how do measures of variability help communicating the dispersion of data?

Answer 4

through the shape and spread of the data distribution

Question 5

examples of measures of variability?

Answer 5

variance, range, quartiles

Question 6

variables?

Answer 6

factors that can take on more than one value

Question 7

what does a distribution represent?

Answer 7

all possible values for a set of data and how frequently those values occur

Question 8

how do discrete data distributions look?

Answer 8

no curve, blocks of rectangles where the height indicates the frequency

Question 9

how do continuous data distributions look?

Answer 9

smooth curve, the area underneath the curve indicates the frequency

Question 10

normal distribution

Answer 10

bell shaped curve

symmetric

uni modal (only 1 peak)

set by mean and standard deviation

Question 11

where is the mean located in a normal distribution?

Answer 11

at the peak

Question 12

what does the standard deviation tell us in a normal distribution?

Answer 12

how thin or flat the curve is

Question 13

standard deviation

Answer 13

the average distance between any point and the mean

Question 14

positive/negative skew?

Answer 14

positive: curve is on the left
negative: curve is on the right

Question 15

distributions where there are two peaks are called…

Answer 15

bimodal data distributions

Question 16

uniform distribution

Answer 16

distribution where there is equal chance of something occurring

Question 17

describing one variable at a time is called…

Answer 17

univariate descriptive statistics

Question 18

good practice with tables

Answer 18

• graphs/tables should be able to stand on their own
• titles should clearly explain what the graph is about
• notes aim to inform the reader about data source
• notes can be used to explain abbreviations/symbols

Question 19

when are pie charts useful?

Answer 19

good at presenting data when:
- discrete
- small number of categories (6 or less)
- exhaustive (total adds up to 100%)

Question 20

characteristics of bar charts

Answer 20

• enables direct comparison
• categories are discrete
• summing across all bars should equal 100% (exhaustive)