Frequency distribution

Question 1

Descriptive statistics

Answer 1

A collection of methods for classifying and summarising the data

Question 2

Two main types of descriptive statistics

Answer 2

• Measure of central tendency

- Measure of variability

Question 3

Frequency distribution

Answer 3

A count of the number of occurrences of each different value in the data set

Question 4

To make a frequency distribution…

Answer 4

1. Count the number of occurrences (frequency) of each value of the DV
2. Make the graph

Question 5

what do we do with a wide range of values?

Answer 5

Group the data into clusters that form a class interval

Question 6

What does a class interval do?

Answer 6

Gives you a way of partitioning the data into meaningful categories to be bale to make sense of it

Question 7

Tips for selecting class interval width -

Answer 7

• Choose width such that 10-20 intervals will cover the range of values
• If possible, choose an odd number interval width

Question 8

Continuous variables…

Answer 8

Can take on any value on the measurement scale

Question 9

What is an exact limit

Answer 9

1/2 unit below and 1/2 unit above the values of the class interval

Question 10

Data curves - frequency polygon

Answer 10

Y-axis - frequency - the frequency of a certain value in your data 
X-axis - mark of the axis with values corresponding to the midpoint of the class interval

Question 11

Three shapes of frequency distributions -

Answer 11

1. Uniform or rectangle
2. Skewed distribution
3. Symmetric distribution (normal distribution)

Question 12

Uniform or rectangle distribution -

Answer 12

evenly distributed throughout the distribution

Question 13

Skewed distribution -

Answer 13

• lots of scores at one end and relatively few at the other end
• can be positive or negative

Question 14

Symmetric/normal distribution -

Answer 14

Two halves of the graph are the same. clumped in the middle with fewer on the outside