Representing Varation Graphically

Question 1

Discontinuous variation

Answer 1

• A characteristic that can only result in certain values
• there can be no in-between values
• variation is determined purely by genetic factors falls into this category
• an animals sex is an example of discontinuous variation as there are only two possible functional values

Question 2

Example of discontinuous variation in microorganisms

Answer 2

Shape of bacteria

• spherical
• rods
• spiral
• comma
• corkscrew shaped

Question 3

How is discontinuous variation represented

Answer 3

Bar chart

Question 4

Continuous variation

Answer 4

Characteristic that can take any value within a range

• there is a graduation in values from one extreme to the other of a characteristic = continuum
• height and mass of plants and animals are examples of such characteristics

Question 5

How is continuous data represented

Answer 5

Collected in a frequency table

These data are plotted onto a histogram

Normally a curve is drawn onto a graph to show the trend

Question 6

Continuous variation data onto a graph

Answer 6

Result in the production of a bell - shaped curve known as a Normal distribution curve

Question 7

Characteristics of a normal distribution

Answer 7

• mean , mode and median are the same
• distribution has a characteristic bell shape which is symmetrical about the mean
• 50% of the values are less than the mean and 50% are greater than the mean
• most values lie close to the mean value - the number of individuals at the extremes are low

Question 8

Standard deviation

Answer 8

Measure of how spread out the data is

Greater the standard deviation = greater the spread of the data

In variation terms
A characteristic which has a high standard deviation = large amount of variation

Question 9

Students t test

Answer 9

Compare the means of data values of two populations

Question 10

Spearman’s rank correlation coefficient

Answer 10

This is used to consider the relationship between two sets of data