Desciptive Statistics

Question 1

What are the 2 descriptive statistics

Answer 1

Measure of central tendency - to see how measurement can be described with the central point
Measure of dispersion - to see how our values disperse away from central tendency

Question 2

Define:

• Histograms
• Bar chart
• Pie chart

Answer 2

Histograms = graphs that show how frequently scores appear in a set
Bar chart = graphs that show the frequency of a particular variable
Pie chart = shows how a variable divides up proportionately

Question 3

Define correlation co-efficient

Answer 3

Measures the strength of the correlation between 2 variables

Question 4

Define dispersions

Answer 4

Measures how well spread a set of scores is

Question 5

Define:

• Mean
• Mode
• Range
• Median

Answer 5

Mean = average 
Mode = most frequent
Range = difference between lowest and highest 
Median = middle score

Question 6

Define raw data

Answer 6

Research results that haven’t had descriptive or inferential statistics applied to them

Question 7

Define:

• Sampling errors

- Sampling distribution

Answer 7

Sampling error = happens when sample scores are unrepresentative of a population’s score
Sampling distribution = assymetical distribution

Question 8

Define standard deviation

Answer 8

The average by which each score in a set differs from the mean

Question 9

Define z score

Answer 9

• Measure how many standard deviations a score lies above or below
• Can be used to find out exactly how many people scored the same/less/more that a particular participant

Question 10

Define:

• Normal distribution

- Skewed distribution

Answer 10

Normal = distribution that has a symmetrical shape on a graph; median, mode, mean are alls same
Skewed = distribution that is lop-sided on graph

Question 11

Define:

• Descriptive statistics

- Inferential statistics

Answer 11

Descriptive = summarises data, makes data easier to understand
Inferential = helps us decide how probable it is that our data is down to chance, helps us decide if results are significant