graphs

Question 1

bar chart

Answer 1

• used to represent discrete data where the data is in categories (x-axis) and mean/frequency (y-axis)

Question 2

histogram

Answer 2

• used to represent continuous data
• columns touch because each one forms a single score on a related scale
• scores (x-axis) - height of column shows frequency (y-axis) of values

Question 3

difference between bar chart and histogram

Answer 3

bar chart - discrete data
histogram - continuous

Question 4

what is a correlational study?

Answer 4

no variables are manipulated
two co-variables are measured and compared to look for a relationship

Question 5

what are co-variables?

Answer 5

the 2 factors/ variables that are measured by the researcher and then compared to each other

Question 6

advantages of correlational analysis

Answer 6

• can be used when it would be unethical/impractical to conduct an experiment
• if correlation is significant, then further investigation is justified
• if correlation is insignificant, you can rule out a causal relationship

Question 7

disadvantages of correlational analysis

Answer 7

• correlational analysis cannot demonstrate a cause and effect relationship between variables
• there may be other unknown variables that can explain why the co-variables being studied are linked
• extraneous variables may lead to false conclusions

Question 8

correlation coefficient

Answer 8

• no. between 0-1
• tells us how strong the correlation is
• near to 1 - stronger correlation
• positive or negative - positive or negative correlation
• cannot establish cause and effect using correlation
• you may find a strong link but it doesn’t mean it caused the event

Question 9

positive correlation

Answer 9

both variables increase together

Question 10

negative correlation

Answer 10

as one variable increases the other decreases

Question 11

no correlation

Answer 11

no relationship between variables

Question 12

scatter graphs

Answer 12

• used for measuring the relationship between two variables
• data from one variable is presented (x-axis) and the other (y-axis)
• x on graph where variables meet
• pattern of plotted points reveal types of correlation
• when two or more variables (co-variables) are measured in order to identigy if there is a relationship between them e.g. height and shoe size
• a single numerical value is produced that is used to describe the relationship

Question 13

normal distribution

Answer 13

• a symmetrical spread of frequency data that forms a bell-shaped curve.
• the mean, median and mode are located at the highest peak

Question 14

skewed distribution

Answer 14

a spread of frequency data that is not symmetrical where the data clusters to one end

Question 15

negatively skewed

Answer 15

a type of distribution in which the long tail is on the negative side of the peak and most of the distribution is concentrated on the right

Question 16

positively skewed

Answer 16

a type of distribution in which the long tail is on the positive side of the peak and most of the distribution is concentrated on the left