IGNOU MSTE-03 Biostatistics-I - Latest Solved Assignment

1. State whether the following statements are True or False. Give reason in support of your answer:

(a) Suppose A is the exposure and B is a confounding factor for outcome C, then there will be a path from A to C via B.
(b) Doing exercise may also be a regimen.
(c) In clinical trials, a control only may be: treatment or no treatment.
(d) In Greville’s method, the central death rate is more in the life table than the population.
(e) In a slope ratio assay, both regression lines have common slope.

2. Explain with examples:

(a) Various sources of demographic data in India
(b) Types of bioassays
(c) LD50 and ED50

3.(a) Differentiate between complete and abridged life tables.
(b) The data on population and number of deaths for different age groups of Districts A and B in the year 2001 were collected in the following table:

Calculate standardised death rate by direct method, taking population of District A as the standard population.

4. In a parallel-line assay, total 18 guinea pigs, 4 guinea pigs each from 3 different breeds were selected and classified into 4 groups for each breed. Two groups were administered with two doses of the standard preparation and remaining two groups with two doses of the test preparation. The responses of these doses are recorded in the following table:

(i) Determine the dose-response regression models for both preparations.
(ii) Test whether the dose-response curves of both preparations are linear and parallel to each other or not.
(iii) Interpret whether the relative potency and its confidence interval can be computed or not.

5.(a) If D+ and D ̶ denote presence and absence, respectively, of a disease and T+ and T ̶ denote test result as positive and negative, respectively, then on the basis of the following information:

Find: (i) sensitivity (ii) specificity (iii) positive and negative predictive values.
(b) Obtain sample size for the following given information:
δ = 0.04, π1 = 0.72, π2 = 0.84, α = 0.01, β = 0.25

6.(a) Explain design and analysis of data of case control study in detail.
(b) Creatinine excretion is a parameter of kidney function. Generally speaking, lower values indicate better health. This depends on body weight. A researcher conducted a study on creatinine excretion in test group and control group to find the efficacy of a new drug. The subjects were randomly divided. He included 100 subjects in each group but for this exercise consider only 10 subjects in each group. The data obtained on creatinine level in these 10 subjects are as follows:
Test group: 16.6 19.8 17.1 17.0 15.6 20.3 24.7 18.5 17.6 22.0
Control group:23.2 22.0 21.9 16.7 14.2 23.2 24.8 25.5 28.1 21.8

Do you think that creatinine excretion was really lower in the test group on average?

7. Suppose you try a regimen A on 1000 subjects and regimen B on 1600 subjects. Results of the trial show that efficacies of regimen A and B are 76% and 82% respectively. Suppose doctor determines 4% as superiority margin. Can you consider regimen B as superior to regimen A.