10.6 Representing variation graphically

what is discrete/discontinuous variation

• characteristic that can only result in certain values

• no in between values

genetic factors falls into what category of variation

discontinuous/discrete variation

what is an example of discontinuous variation

• an animal’s sex (female or male)

• blood type

how can discontinuous variation be represented

• bar chart

• pie chart

what is continuous variation

• characteristic that can take any value within a range

• graduation in values with two extremes (continuum)

what are examples of continuous variation

• height and mass of plants and animals

what are polygenes

number of genes control characteristics that show continuous variation

what type of data does normal distribution use

continuous

what are characteristics of a normal distribution

• mean, mode and median are the same

• bell-shaped and symmetrical

what is standard deviation

measure of how spread out the data is (greater standard deviation, greater the spread of data)

what percentage of values are within one standard deviation

68% of values

what percentage of values are within two standard deviations

95% of values

what percentage of values are within three standard deviations

99.7% of values

what does the student’s t test compare

compare the means of data values of two populations

what is the spearman’s rank correlation coefficient for

to consider the relationship between two sets of data

when should you reject null hypothesis

• if t-value is more than > critical value

• due to chance

• conclude there is a significant difference

when should you accept null hypothesis

• if t-value is less than < critical value

• not due to chance

• conclude there is no significant difference

how to lay out answer to t-test

• state null hypothesis

• accept or reject null hypothesis

• due or not due to chance