10.6 Representing Varation Graphically Flashcards
What is discontinuous variation
A characteristic that can only result in certain discrete groups of phenotypes
What is an example of discontinuous variation
Blood type, variation determined by purely genetic factors
What is continuous variation?
A characteristic that can take any value within a range
What is an example of continuous variation
Height, often influenced by environmental factors, not controlled by a single gene
How is discontinuous variation represented?
Using a bar chart, or pie chart
What curve is produced for normal distribution?
Bell-shaped
How is discontinuous variation represented?
Collected in a frequency table, then plotted onto a histogram, then a curve is drawn onto the graph to show a trend
What are the characteristics of normal distribution?
-The mean, mode and median are the same
-The distribution has a characteristic ‘bell shape’ which is symmetrical around the mean
-50% of the values are less than the mean, 50% off values are greater than the mean
-Most values lie closer to the mean, the number of individuals at the mean are low
Draw a graph of normal distribution
What is standard deviation?
How spread out the data is (around the mean)
What is the relationship between standard deviation and variation?
The greater the standard deviation, the larger the amount of variation
What are the values found when you calculate the standard deviation of data that displays normal distribution?
-68% of values are within 1 standard deviation of the mean
-95% of values are within 2 standard deviations of the mean
-99.7% of values are within 3 standard deviations of the mean
What is the symbol for standard deviation?
σ
What is the propose of the students t-test?
Compare the means of data values of two populations
What is the propose of the spearman’s rank correlation coefficient?
To consider the relationships between two sets of data
What must occur to be able to use the students t-test?
-Data collected must be normally distributed
-Enough data should be collected to calculate a reliable mean
What is meant by no-correlation (spearman’s rank correlation coefficient)?
No relationship between data (0)
What is meant by positive correlation (spearman’s rank correlation coefficient)?
As one set of data increases in value, the other set of data also increases in value (+1)
What is meant by negative correlation (spearman’s rank correlation coefficient)?
As one set of data increases in value, the other set of data decreases in value (-1)
Draw a graph showing no correlation
Draw a graph showing positive correlation
Draw a graph showing negative correlation
What is the rs value for perfect positive correlation?
+1
What is the rs value for perfect negative correlation?
-1
