Statistics

Question 1

What is the first statistic?

Answer 1

• Standard Deviation

Question 2

What is Standard Deviation?

Answer 2

• It is one of the most important descriptive statistics as it gives a more accurate figure than a range or interquartile range
• This is because it considers all figures and is not affected by extreme values.
• It also shows the extent of the variations from the mean.

Question 3

What does the Standard Deviation do differently from the range?

Answer 3

• It measures the spread of data from the mean, while the range measures the two extreme values in the data set.

Question 4

What is the second statistic?

Answer 4

• Chi Squared

Question 5

What is Chi Squared?

Answer 5

• This can test the associations between variables.
• It is one of the most widely used and versatile tests of association.

Question 6

What can Chi Squared be compared with?

Answer 6

• Significance tables
• This is to confirm whether the difference between the observed data and the expected data is a chance effect or a statistical significance.

Question 7

What should the Chi Squared data have?

Answer 7

• Sample should include 20 observations in each area.
• The data should be in the form of frequencies.
• The data have must precise numerical value, for example you cannot use %’s.
• The data must be organised into categories or groups.
• The expected frequency in one category should be greater than 5 or else the statistic won’t work.

Question 8

What is the third statistic?

Answer 8

• Nearest Neighbour Analysis

Question 9

What is Nearest Neighbour Analysis? (NNA)

Answer 9

• It can be used to identify a tendency towards clustering or dispersion of data-sets.

Question 10

What is the 3 types the data could be?

Answer 10

• Clustered = 0, the dots are close to the same point
• Random = 1.0, there is no pattern
• Regular = 2.15, perfectly uniformed pattern.

Question 11

What is are the disadvantages of NNA?

Answer 11

• It cannot always distinguish between single and multi-clustered distribution.
• An index of 1.0 doesn’t always mean a random distribution as it may be related to a second unmapped factor e.g villages may give a 1.0 but they may be situated around springs.

Question 12

What is the fourth statistic?

Answer 12

• Spearman’s Rank Correlation Coefficient

Question 13

What is Spearman’s?

Answer 13

• The test is quick and can be easily calculated in comparison to Pearson’s.
• The test uses data which can be ranked but this means that it loses some of its accuracy as it is not using the actual values.

Question 14

What are the advantages + disadvantages of Spearman’s?

Answer 14

• It can only test for linear relationships so a scatter graph could be drawn to see if this is the case.
• It requires a sample size of at least 7 observations, however, the longer the sample size, the more reliable the result.

Question 15

What is the fifth statistic?

Answer 15

• Pearson’s Product Movement Correlation Coefficent

Question 16

What is Pearson’s?

Answer 16

• It is the most widely used correlation method.
• It tests the strength of correlation between two variables.
• It is a more powerful method than Spearman’s because it uses the actual values instead of ranks to examine the relationship between two variables.

Question 17

What can we do with Pearson’s and what do we need?

Answer 17

• Ideally need 12-15 data values in order to be an efficient statistic.
• Can draw scatter graph of the results to visually confirm there is a correlation between two data sets.

Question 18

What is the final statistic?

Answer 18

• Linear Regression

Question 19

What is Linear Regression?

Answer 19

• This is the most commonly used method of predictive analysis to determine the linear relationship between one independent variable and one dependent variable.

Question 20

What does Linear Regression allow us to calculate?

Answer 20

• It allows us to understand how much the dependent value will change when we change the independent variable.
• The regression equation allows us to calculate the best-fit line on the scatter graph mathematically and by doing this, it’s more certain than plotting it by eye.
• Allows us to predict trends + future values.