RM - Display of quantitative data and data distributions

Question 1

What is a bar chart?

Answer 1

A graph used to represent the frequency of data; the categories on the x-axis have no fixed order and there is no true zero.

Question 2

What is a histogram?

Answer 2

A type of frequency distribution in which the number of scores in each category of continuous data are represented by vertical columns. There is a true zero and no spaces between the bars.

Question 3

What does it mean if there is a negative skewed distribution?

Answer 3

Most of the scores are bunched towards the right. The mode is to the right of the mean because the mean is affected by the extreme scores tailing off to the left.

Question 4

What does it mean if there is a normal distribution?

Answer 4

A symmetrical bell-shaped frequency distribution. This distribution occurs when certain variables are measured, such as IQ or the life of a light bulb. Such ‘events’ are distributed in such a way that most of the scores are clustered close to the mid-point; the mean, median and mode are at the mid-point.

Question 5

What does it mean if there is a positive skewed distribution?

Answer 5

Most of the scores are bunched towards the left. The mode is to the left of the mean because the mean is affected by the extreme scores tailing off to the right.

Question 6

What does is mean if there is a skewed distribution?

Answer 6

A distribution is skewed if one tail is longer than another, signifying that there are a number of extreme values to one side or the other of the mid-score.

Question 7

How to you display quantitative data?

Answer 7

Graphs and tables.

Question 8

What are 5 key points on how graphs/tables should be drawn/what should they include?

Answer 8

Simple so easily read.
Clearly show the findings from the study.
Have a short but informative title.
Clearly labelled axis.
Use squared paper if hand-drawing graphs.

Question 9

Which variable goes on the x-axis?

Answer 9

Independent

Question 10

What are the measurements collected in a research study referred to as?

Answer 10

Raw data

Question 11

What does ‘raw data’ mean?

Answer 11

Numbers (measurements) that haven’t been before any descriptive statistics have been carried

Question 12

What data is set out in a table?

Answer 12

Raw data

Question 13

How can raw data be set out?

Answer 13

In a table and/or summarised using measures of central tendency and dispersion.

Question 14

What are summary tables useful for?

Answer 14

Interpreting findings.

Question 15

What does the height of each bar in a bar chart represent?

Answer 15

The frequency of each item.

Question 16

What are bar charts suitable for?

Answer 16

Data that isn’t continuous (has no particular order) such as categorical or nominal data.

Question 17

Are there gaps in bar charts between bars?

Answer 17

Yes

Question 18

Why are there gaps in between bar chart bars?

Answer 18

To indicate the lack of continuity.

Question 19

How is a histogram different to a bar chart?

Answer 19

In a histogram, the area between the bars must be proportional to the frequencies represented.

Question 20

What type of data has to be shown on the x-axis of a histogram and what doe this mean?

Answer 20

Continuous meaning you can’t draw a histogram with data in categories.

Question 21

Can you draw a histogram with data in categories?

Answer 21

No because it is a representation of continuous data only.

Question 22

Are there gaps between bars in a histogram?

Answer 22

No

Question 23

What does a line graph have on the x-axis?

Answer 23

Continuous data

Question 24

How does a line graph represent data?

Answer 24

Dots at the top of each ‘bar’ with lines joining up the dots.

Question 25

What are scatter diagram used for?

Answer 25

Correlational analysis

Question 26

What is a distribution?

Answer 26

The overall pattern of data.

Question 27

What shape is the normal distribution?

Answer 27

A classic bell-shaped curve.