Week 4 - Review of Descriptive Statistics

Question 1

Descriptive Statistics

Answer 1

statistics simply to describe data collected, both sample and population

Question 2

Inferential Statistics

Answer 2

Using sample to infer something about a population

Question 3

Characterising a data set

Answer 3

• central tendency (mean, median, mode)
• variability (SD, sum of squares, variance)
• shape (modality, skew, kurtosis)

Question 4

Shape of Distributions

Answer 4

Unimodal - scores vary around one central point
Bimodal - scores vary around two central points
Modality - the number or central clusters that a distribution possesses

Question 5

Kurtosis

Answer 5

‘peakedness’ - how tightly clustered are scores around the mean

Question 6

Skew

Answer 6

The symmetry of the tails of the distribution

Question 7

Normality characteristics

Answer 7

• distribution is unimodal
• has moderate peakedness
• has symmetric tails

Question 8

Z-Score

Answer 8

How many standard deviations away from the mean a particular score is

Question 9

Types of distributions

Answer 9

• Population
• Sample
• Distribution of means

Question 10

Standard error of the mean

Answer 10

The sample SD divided by the square root of the number of observations in the sample

Question 11

T-tests

Answer 11

Used when the population mean is known, but the SD is not known

Question 12

One sample T-Test

Answer 12

Examines whether the mean of a population is statistically different from a known or hypothesised value

Question 13

Independent Sample T-Test

Answer 13

Used to compare two sample means from unrelated groups

Question 14

Paired Samples T-Test

Answer 14

Compares the means from two variables of a single group