This topic describes the available options for significance by column/row calculations.
The options on significativity by column window allows you to compare the column profile for each column in pairs. To access these options, click advanced options... when creating or editing a calculation. The options are as follows:
Test each column against: Select what comparison will be made, as follows:
All columns: all the columns of the same question or different questions will be compared with each other. For example, if the questions Gender and Age are shown in columns, the comparison is for...
A: Man
B: Woman
C: Less than 24
D: 24-34 years
E: 35 and over
or
A versus B (Man versus Woman)
A versus C (Man versus Age less than 24)
A versus D (Man versus Age 24-34)
A versus E (Man versus Age 35 and over)
B versus C (Woman versus Age less than 24)
B versus D (Woman versus Age 24-34)
B versus E (Woman versus Age 35 and over)
C versus D (Age under 24 versus Age 24-34)
C versus E (Age under 24 versus Age 35 and over)
D versus E (Age 24-34 versus Age 35 and over)
All columns of the question: all the columns of the same question only will be compared with each other. For example, if questions Gender and Age are shown in columns, the comparison is for...
A: Man
B: Woman
C: Less than 24
D: 24-34 years
E: 35 and over
or
A versus B (Man versus Woman)
C versus D (Age under 24 versus Age 24-34)
C versus E (Age under 24 versus Age 35 and over)
D versus E (Age 24-34 versus Age 35 and over)
Total only: all the columns of the same question or different questions will be compared to the total column. All columns of the question and the corresponding response edges: all the columns of the same question only will be compared with each other and with the corresponding edge. For example, if the question Gender is shown in edge and Age in column, the comparison is for...
A: Man (edge)
B: Less than 24
C: 24-34 years
D: 35 and over
E: Woman (edge)
F: Less than 24
G: 24-34 years
H: 35 and over
or
A versus E (Man versus Woman)
B versus C (Age under 24 versus Age 24-34)
B versus D (Age under 24 versus Age 35 and over)
C versus D (Age 24-34 versus Age 35 and over)
B versus F (Man: Age under 24 versus Woman: Age under 24)
C versus G: (Man: Age 24-34 versus woman: Age 24-34)
D versus H: (Man: Age 35 and over versus Woman: Age 35 and over)
Previous column only: all the columns of the same question or different questions will be compared to the previous column.
All columns of the question and the corresponding question edges: all the columns of the same question only will be compared with each other and with the corresponding edge.
All columns of edge response: columns are only tested if they are within the same edge response. All columns of the current question and the first question. all columns are tested against each other if they are in the same question, OR against a column of the first question.
Show letter in: Select the priority for the display of letters, as follows:
Both columns: the significance will appear in both columns. For example:
|
Favourite colour |
Men: 76 |
Women: 74 |
Sample: 150 |
|
|
A |
B |
|
|
Red: |
15 |
25 |
40 people |
|
Profile column |
19.7% |
33.8% |
30 people |
|
Significance by column |
B |
A |
|
First column: the significance will appear in the first column. For example:
|
Favourite colour |
Men: 76 |
Women: 74 |
Sample: 150 |
|
|
A |
B |
|
|
Red: |
15 |
25 |
40 people |
|
Profile column |
19.7% |
33.8% |
30 people |
|
Significance by column |
B |
|
|
|
Favourite colour |
Men: 76 |
Women: 74 |
Don't Know: 10 |
|
|
A |
B |
C |
|
Red: |
15 |
25 |
8 |
|
Profile column |
19.7% |
33.8% |
80% |
|
Significance by column |
|
A |
|
Using: Specifies the type of test to be used: classical student test, student test using estimator, student test using efficiency coefficient, or student test using estimator and efficiency coefficient.
Test against total column: When this option is selected, the total column becomes a column like any other for the purposes of the calculation.
Display minus if under: When this option is selected, a minus sign is shown if the significancy goes down. This can be used in conditional formatting when you test in conjunction with the column before: if there are two letters, the value has significantly gone down, if you have one, it has gone up.
Use student test when degrees of freedom: If this option is selected, a student test will be used when the degrees of freedom are less than the amount stated in the adjacent box.
Columns are assumed independent: When this option is selected, the individuals belonging to a sub-total will be considered different to those present in the category grouped in the same sub-total.
Count threshold: The minimum count to be taken into account in a cell.
Base threshold: The minimum base to be taken into account in a cell.
High significativity (%): The percentage at which values are to be regarded as highly significant.
Normal significativity (%): The percentage at which values are to be regarded as of normal significance.
Low significativity (%): The percentage at which values are to be regarded as of low significance.
Display "A+": Mark highly significant values with A+.
Display "A": Mark highly significant values with A.
Display "a": Mark highly significant values with a.
In the results, significant values will be indicated by letters, as follows (if the corresponding display options described above are selected):
High significance: "A+"
Medium significance: "A"
Low significance: "a"
Proportions are calculated as follows:
p1= Proportion 1 observed in the sample
n1=Sample size
p2= Proportion 2 observed in the sample
n2=Sample size
tα= 90% = 1.65
tα= 95% = 1.96
tα= 99% = 2.576
We calculate 'D', which follows a normal mathematical expectation law p1-p2, and standard deviation sd=squared ROOT((p1*(1-p1))/n1 + (p2*(1-p2))/n2),
(P1-P2)
D= --------------------------------------------------------
P1*(1-P1) P2 * (1 - P2)
Root (----------------- + ------------------- )
N1 N2
=> if abs(D)> tα = Significant difference
Means are calculated as follows:
m1= Mean 1 observed in the sample
sd1= Standard deviation 1 observed in the sample
n1=Sample size
m2= mean 2 observed in the sample
sd2= Standard deviation 2 observed in the sample
n2=Sample size
tα= 90% = 1.65
tα= 95% = 1.96
tα= 99% = 2.576
We calculate 'D', which follows a normal mathematical expectation law m1-m2=0, and standard deviation sd=root( sd1 ²/ n1 + sd2²/n2),
(m1-m2)
D= --------------------------------------------------------
squared root( sd1 ²/ n1 + sd2²/n2)
=> if abs(D)> tα = Significant difference