10.6 Representing variation graphically Flashcards
(17 cards)
What is discontinuous variation?
A characteristic that can only result in certain values
What is discontinuous variation usually represented by?
A bar or pie chart
What is continuous variation?
A characteristic that can take any value within a range
What is continuous variation usually represented by?
Histograms, line charts
What is a normal distribution curve?
A bell curve shape
What are the characteristics of a normal distribution curve?
-Mean, mode, median are the same
-Distribution has a bell shape, symmetrical about the mean
-Most values lie close to the mean
What is standard deviation?
A measure of how spread out the data is. The greater the standard deviation, the greater the spread of the data
What is the advantage of using the standard deviation rather than the range?
It is more meaningful and eliminates the effect of anomalies.
What is Spearman’s Rank Correlation Coefficient used to do?
Measures the strength of the correlation between 2 sets of data.
What is the range of values for Spearman’s Rank Correlation Coefficient?
-1 to +1
How do you calculate the degrees of freedom?
n-1
What is student’s t test used for?
Comparing the mean values of 2 sets of data, seeing if there is a correlation
What are the types of data that a student’s t test can have?
Paired or unpaired data
What is paired data?
2 groups of data that are related
What is unpaired data?
2 groups of data that are independant of eachother (e.g from different populations)
What is a null hypothesis?
The claim that no relationship exists between data.
What is the Chi squared test used for?
Looking for a significant difference between observed and expected results
