Statistics

Question 1

Are statistics a method of data gathering or data processing?

Answer 1

Processing

Question 2

What are the measures of central tendency?

Answer 2

The mean, median and mode

Question 3

What is the mean?

Answer 3

Average value of a group of statistical data

Question 4

What is the median?

Answer 4

Middle value of the group

Question 5

What is the mode?

Answer 5

The value that appears most regularly in the group

Question 6

What is standard deviation?

Answer 6

The measure of the average amount by which the data differs from the mean

Question 7

Advantages of standard deviation:

Answer 7

+ shows variety
+ easy to describe, as not square units
+ data is likely to be similar and, therefore, easy to process

Question 8

Disadvantages of standard deviation:

Answer 8

Easily affected by anomalies

Question 9

What is the standard error of the mean?

Answer 9

The measure of the accuracy of a sample mean, as an estimate of the total population mean

Question 10

What is chi squared

Answer 10

Determines the differences between observed and expected data, as well as whether or not this is due to explainable factors.

Question 11

How do you carry out chi squared?

Answer 11

Use formula: compare expected and observed averages. Compare test statistic to 95% significance level. Prove or disprove null hypothesis

Question 13

Advantages of chi squared

Answer 13

+ Determines a significance level - easy analysis

+ useful if data can be grouped

Question 14

What is spearman’s rank correlation coefficient

Answer 14

A test that measures the strength and direction of a relationship between two variables

Question 15

How do you carry out spearman’s rank

Answer 15

Use formula: compare the squared value of their differences by the number of values
Determine if positive or negative correlation
Determine if significant or not

Question 16

What are spearman’s ranks significance levels?

Answer 16

\+ 0-0.19 = weakest correlation 
\+ 0.20-0.39 = weak correlation 
\+ 0.40-0.59 = moderate correlation 
\+ 0.60-0.79 = strong correlation 
\+ 0.80-1 = strongest correlation

Question 17

Advantages of spearman’s rank:

Answer 17

+useful if the data is ordinal (rank able)
+ identifies comparable relationships
+ identifies nature of correlation
+ quicker to calculate than pearson’s

Question 18

Disadvantages of spearman’s rank:

Answer 18

+ requires 7 pairs of data
+ ranking of data ignores magnifiques of differences
+ does not give reasons for difference

Question 19

What is pearsons’ product moment correlation coefficient?

Answer 19

Similar to spearman’s. Measures strengths if a linear relationship between two variables

Question 20

What are the advantages of Pearson’s coefficient?

Answer 20

+ identifies relationship between two variables
+ identifies nature of correlation
+ Uses actual values, not ranked, so raw data is not lost
+ useful if data is normally distributed
+ increasingly precise

Question 21

What are the disadvantages of Pearson’s coefficient?

Answer 21

+ time consuming
+ doesn’t explain correlation
+ affected by extreme values
+ assumes all relationships are linear

Question 22

What is the nearest neighbour index?

Answer 22

A statistic that measures the distribution between data sets, according to whether they are clustered, random or regular.

Question 23

What is the measuring values of the nearest neighbour index?

Answer 23

0 - 2.15

0 is clustered
1 is random
2.15 is regular

Question 24

How do you carry out the nearest neighbour index?

Answer 24

Measure distance between the two sites
Compare distance to average distance between sites of entire area
Insert values into formula
Compare to previous values to determine if the distribution is random, regular or clustered.

Question 25

Advantages of nearest neighbour index:

Answer 25

+ increasingly objective
+ easy to compare areas
+ allows change over time to be identified

Question 26

Disadvantages of nearest neighbour index:

Answer 26

+ dependent on the side of the area + number does not actually represent pattern, only general overview + some nearest neighbours may be out of sample area + larger areas may end up in exaggerate patterns of clustering

Question 27

What is linear regression analysis?

Answer 27

A statistic that determines the lineal relationship between a dependant and an independent variable. Plotted with line of best fit.

Question 28

Advantages of linear regression analysis:

Answer 28

+ determine strength by measuring surrounding clustering + correlation is visually determined - easy to comprehend + dimple calculation + future trends can be calculated

Question 29

Disadvantages of linear regression:

Answer 29

+ must already have a correlation to present, have to completed spearman’s (for example) beforehand. + no reasoning + no nature of correlation, might be chance

Question 30

What is a location quotient?

Answer 30

A method of quantifying the concentration of a certain variable in one area, compared to the national mean

Question 31

Advantages of a locational quotient:

Answer 31

+ quick and easy to calculate | + clearly shows concentration, when compared with a graph

Question 32

Disadvantages of a locational quotient:

Answer 32

+ raw data is lost as percentages are used + figure may be hard to interpret + no explanation of pattern

Question 33

What is variance?

Answer 33

The measure of how far a data set is spread out

Question 34

Advantages of variance:

Answer 34

+ quick and simple to calculate + squaring data ensures results are not zero + useful if data is normally distributed

Question 35

Disadvantages of variance:

Answer 35

+ doesn’t shows if the correlation is positive or negative + hard to interpret + raw data is lost as units are squared + can be influenced by extreme values

Question 36

Disadvantages of chi squared

Answer 36

+ doesn’t show scale of difference + needs at least 20 data values + complicated formula + trends are not shown by averages and could be affected by anomalies