Faculty of Health, Medicine and Life Sciences
1.1.1 Seminar 4.2 assignments
Problem 1
The p-value as obtained in the chi-square test for a contingency table expresses:
a. how likely it is to obtain the observed chi-square value or an even larger value if there
is no relation between the row and column variable
b. how likely it is to obtain the observed chi-square value or an even smaller value if
there is no relation between the row and column variable
c. how likely it is to obtain the observed chi-square value or an even larger value if there
is a relation between the row and column variable
d. how likely it is to obtain the observed chi-square value or an even smaller value if
there is a relation between the row and column variable
Answer:
It tests the null-hypothesis so no relation between the row and column variable since they are
independent from each other. The observed chi square moves left or right in the chi-square
distribution.
Problem 2
If the p-value of the chi-square test for a contingency table is below the significance level alfa,
our conclusion is that:
a. there is no relation between the row and column variable
b. there is a very strong relation between the row and column variable
c. there is a negative relation between the row and column variable
d. there is a relation between the row and column variable.
Answer:
If the p-value of the chi-square test for a contingency table is below the significance level alfa: it
means that the null hypothesis will be rejected since evidence against it will be strong. The null
hypothesis indicates that there is no relationship. The alternative hypothesis will be accepted
which indicates a relationship.
Problem 3
Suppose the p-value of the chi-square test for a 2x2 contingency table is below the
significance level alfa = 0.10. Which interpretation is most correct?
a. there is enough counterevidence against the null hypothesis, so we reject it
b. there is enough counterevidence against the alternative hypothesis, so we reject it
c. the probability of the null hypothesis being true is below 10%, so we reject it
d. the probability of the alternative hypothesis being true is below 10%, so we reject it
Answer:
A p-value below the significance level alpha means that there is strong evidence against the
null hypothesis.
Problem 4
Suppose we perform an experiment into the effect of biofeedback (Yes or No) on a person’s
blood pressure (too high or not). Suppose the p-value of the chi-square test for the resulting
2x2 contingency table is above the significance level alpha. What is your conclusion?
In the population the relative risk for having a too high blood pressure:
a. is equal to 1
BBS1003 Syllabus 2020-2021 202020
1.1.1 Seminar 4.2 assignments
Problem 1
The p-value as obtained in the chi-square test for a contingency table expresses:
a. how likely it is to obtain the observed chi-square value or an even larger value if there
is no relation between the row and column variable
b. how likely it is to obtain the observed chi-square value or an even smaller value if
there is no relation between the row and column variable
c. how likely it is to obtain the observed chi-square value or an even larger value if there
is a relation between the row and column variable
d. how likely it is to obtain the observed chi-square value or an even smaller value if
there is a relation between the row and column variable
Answer:
It tests the null-hypothesis so no relation between the row and column variable since they are
independent from each other. The observed chi square moves left or right in the chi-square
distribution.
Problem 2
If the p-value of the chi-square test for a contingency table is below the significance level alfa,
our conclusion is that:
a. there is no relation between the row and column variable
b. there is a very strong relation between the row and column variable
c. there is a negative relation between the row and column variable
d. there is a relation between the row and column variable.
Answer:
If the p-value of the chi-square test for a contingency table is below the significance level alfa: it
means that the null hypothesis will be rejected since evidence against it will be strong. The null
hypothesis indicates that there is no relationship. The alternative hypothesis will be accepted
which indicates a relationship.
Problem 3
Suppose the p-value of the chi-square test for a 2x2 contingency table is below the
significance level alfa = 0.10. Which interpretation is most correct?
a. there is enough counterevidence against the null hypothesis, so we reject it
b. there is enough counterevidence against the alternative hypothesis, so we reject it
c. the probability of the null hypothesis being true is below 10%, so we reject it
d. the probability of the alternative hypothesis being true is below 10%, so we reject it
Answer:
A p-value below the significance level alpha means that there is strong evidence against the
null hypothesis.
Problem 4
Suppose we perform an experiment into the effect of biofeedback (Yes or No) on a person’s
blood pressure (too high or not). Suppose the p-value of the chi-square test for the resulting
2x2 contingency table is above the significance level alpha. What is your conclusion?
In the population the relative risk for having a too high blood pressure:
a. is equal to 1
BBS1003 Syllabus 2020-2021 202020
