NEW
Font size
WorksheetsProportion Difference Test
Total questions: 25
Worksheet time: 13mins
The 4x5 contingency table has how many cells?
9
12
18
20
24
The 4x5 contingency table has degrees of freedom of?
9
12
18
20
24
A study wants to analyze whether or not there are differences in bruxism between men and women. What test will be used?
Continuity Correction if there is expected count of less than five in more than 20 percent cells
McNemar if there is no expected count less than five in more than 20 percent cells
Pearson if there is no expected count less than five in more than 20 percent cells
Cochrans Q if there is an expected count of less than five in more than 20 percent cells
Fisher Exact Test if there is expected count of less than five in more than 20 percent cells
In the unpaired comparative test with categorical independent and dependent variables more than 2x2 and there is no expected count of less than 5, nor more than 20% of the number of cells, what test will be used?
Pearson Chi Square
Mann Whitney
McNemar
Continuity Correction
Fisher Exact
The parameter of Chi-Square distribution is?
Number of columns
Degrees of freedom
Number of cells
Number of rows
None of the options
If for a contingency table df=12 and number of rows is 4 then the number of columns will be?
4
2
3
5
1
A study is aimed to analyze whether or not there are differences in tooth erosion proportion after fluor application. What test will be used?
McNemar if there is no expected count less than five in more than 20 percent cells
Continuity Correction if there is no expected count less than five in more than 20 percent cells
Cochrans Q if there is no expected count of less than five in more than 20 percent cells
Fisher Exact Test if there is an expected count less than five in more than 20 percent cells
McNemar if there are two measurement times
In general, in the x2 test, the greater the difference (O-E) in each cell, then?
The chance to reject the null hypothesis is getting bigger
The smaller the value of x2
The greater the value of x2
The chance of not rejecting the null hypothesis is getting bigger
The opportunity not to reject the alternative hypothesis is getting bigger
In the chi-square (x2) test, the null hypothesis is true if?
The "Observed" frequency is very different from the "Expected" frequency
"Observed" frequency is higher than "Expected" frequency
"Observed" frequency is lower than "Expected" frequency
The "Observed" frequency is approximately the same as the "Expected" frequency
None of the options
The column total indicates the study design is?
Cohort
Survey
Cross sectional
Case Control
All except case control
The row total indicates the study design is?
Cohort
Survey
Cross sectional
Case Control
All except case control
Which of the following is not a property of the Chi-Square distribution?
Negative skewed
Positive skewed
Close to normal if degree of freedom is large
one-tailed distribution
one peak distribution
The chi square statistical test is used in data analysis with the following objectives?
Knowing the relationship between having a bad thumb sucking habit and the presence of malocclusion in children
Knowing whether there is a difference in the average duration of brushing teeth between boys and girls
Knowing whether there is a relationship between the length of education with the amount of income
Knowing the relationship between the level of oral hygiene with the average dmft
Knowing the magnitude of association between mother’s education levels with the plaque index level
In the chi square test for a 3x2 table, if one cell has a value <5 (but not 0) then we should?
Take the p value from continuity correction
Take Pearson's p value
Take the p value from Fisher exact
Perform a Mann-Whitney analysis
Change the 3 categories to 2 categories variable
Which factor that does not influence the degree of freedom (dk) in hypothesis testing using chi-square?
number of lines
number of columns
sample size
number of categories
level of significance
What is the function of a contingency table, in the context of bivariate analysis?
It shows the results you would expect to find by chance
It summarizes the frequencies of two variables so that they can be compared
It lists the different levels of p value for tests of significance
It compares the results you might get from various statistical tests
It shows the possibility of getting a non-significant result
How to calculate Expected counts from Observed counts?
From Chi square table
(subjects in cell a + subjects in cell b)/row total
(row total subjects*column total subjects)/grand total subjects
(r-1)*(c-1)
(subjects in cell a + subjects in cell c)/column total
Chi square values ranges from?
-1 to +1
0 to + infinity
0 to 100
– infinity to + infinity
-3 SD to +3 SD
X2 critical value for df=1, alpha=0.05 from X2 table is 3.841. If the calculated X2 is >3.841, it means?
Null hypothesis is rejected
Null hypothesis is not rejected
Alternative hypothesis is rejected
Alternative hypothesis not accepted
More information is needed for conclusion
What is the value of X2 critical value for df=2, alpha=0.05 from X2 table?
0.831
1.064
2.706
3.841
5.991
Which number that cannot be possible as the value of X2?
0
-1
1
2
3
The chi-square distribution is?
Positively skewed, with no values less than zero
Negatively skewed, with no values greater than zero
Positively skewed, with values from zero to positive infinity
Negatively skewed, with values from zero to negative infinity
Symmetrical, centered at a value determined by the degrees of freedom
A researcher obtains a value of -8.50 for a chi-square statistic. What can you conclude from the value?
The observed frequencies are consistently larger than the expected frequencies
Inconclusive because the value of chi-square cannot be negative
The expected frequencies are consistently larger than the observed frequencies
There are large differences between the observed and expected frequencies
None of above
Which of these statements that is false about Risk?
Can be calculated if the contingency table is 2x2
It measures the strength or magnitude of association between dependent and independent variables
The risk value will always be positive
Its interpretation depends on study design
None of the above
Which one of these statements about Fisher exact test that is false?
Applies to 2x2 table
Usually gives larger probability than other chi square test
It is suitable when expected counts is small
It is difficult to calculate when expected counts is big
Usually gives smaller probability than other chi square test
