Biostatistics is a fundamental tool in medical education and practice that supports evidence-based decision-making at every stage of a doctor’s career. For MBBS students and practicing doctors, it helps in understanding medical literature, interpreting diagnostic tests, and analyzing patient data for rational clinical care. For PG residents, biostatistics is essential in designing studies, calculating sample size, selecting appropriate statistical tests, analyzing data, and writing a valid thesis. For faculty members, it plays a crucial role in conducting high-quality research, interpreting results accurately, guiding students, and publishing scientific articles in peer-reviewed journals, thereby contributing to the advancement of medical science.
#A. DESCRIPTIVE STATISTICS
#1.
Construct a Frequency Table with Tally Bar, Histogram, and Frequency Polygon from the given data of children’s birth weight.
(2 + 2 + 2 = 6)
1.2, 4.0, 3.5, 3.1, 3.2, 4.1, 2.5, 2.2, 2.5, 2.6, 2.8, 2.9, 1.7, 3.2, 3.1, 2.7, 2.8, 2.6, 2.5, 2.1, 2.3, 1.5, 3.8, 3.6, 1.9, 2.7, 2.9, 3.2, 3.3, 3.0, 3.8, 4.0, 3.2
#2.
Calculate Mean, Median, First Quartile, Third Quartile, Fourth Decile and 35th Percentile using the information given below.
(2 + 2 + 2 + 2 + 2 + 2 = 12)
Wage | 20 | 30 | 40 | 50 | 60 |
|---|---|---|---|---|---|
No. of workers | 5 | 12 | 14 | 4 | 2 |
#3.
Calculate the following measures for the distribution of weight of a random sample of 30 adolescents.
Weight (kg) | 20–30 | 30–40 | 40–50 | 50–60 | 60–70 |
|---|---|---|---|---|---|
No. of respondents | 5 | 12 | 8 | 3 | 2 |
a. Interquartile Range (2)
b. Mean Deviation (2)
c. Standard Deviation (2)
d. Variance (1)
e. Coefficient of Variation (1)
#4.
A cross-sectional survey observed the following data on infant weight.
Compare mean and standard deviation of each group and identify which data represents a better mean with justification.
(2 + 2 + 2 + 2 + 2 = 10)
Male: (5, 8, 4, 7, 4, 7, 9, 10, 8, 9)
Female: (4, 6, 7, 5, 8, 5, 7, 9, 8, 7)
#5.
Calculate the following measures based on the distribution of children ever born of a random sample of 30 mothers.
Children Ever Born (x) | 2 | 3 | 4 | 5 | 6 |
|---|---|---|---|---|---|
No. of respondents (f) | 5 | 10 | 8 | 5 | 2 |
a. Mean, First Quartile and Third Quartile (2 + 2 + 2)
b. Standard Deviation (2)
c. Construct a suitable graph (2)
#6.
A cross-sectional survey was conducted in Biratnagar city among 40 women.
Weight (kg) | 30–40 | 40–50 | 50–60 | 60–70 |
|---|---|---|---|---|
Frequency | 6 | 12 | 18 | 4 |
a. Find Mean, Median and Mode (2 + 2 + 2)
b. Calculate Standard Deviation (2)
c. Present the data in a Histogram (2)
#7.
Distribution of children ever born of a random sample of 30 mothers is given below.
Children Ever Born (x) | 2 | 3 | 4 | 5 | 6 |
|---|---|---|---|---|---|
No. of respondents (f) | 5 | 10 | 8 | 5 | 2 |
a. Mean, First Quartile and Third Quartile (2 + 2 + 2)
b. Standard Deviation (2)
c. Construct a suitable graph (2)
#8.
Distribution of pulse rate of a random sample of 30 individuals is given below.
Pulse Rate | 60–70 | 70–80 | 80–90 | 90–100 | 100–110 |
|---|---|---|---|---|---|
Frequency | 5 | 10 | 8 | 5 | 2 |
a. Calculate Mean and Mode (2 + 2)
b. Calculate Standard Deviation (3)
#9.
Construct a Circular Graph and a Simple Bar Diagram from the following data.
(2 + 2 = 4)
Province | Koshi | Madesh | Bagmati | Gandaki | Karnali |
|---|---|---|---|---|---|
Infants (‘000) | 350 | 610 | 380 | 300 | 200 |
#10.
Age of under-five children recorded in Pediatrics OPD of BMTCH is given below:
7, 12, 8, 13, 9, 7, 6, 11
Find Interquartile Range and Standard Deviation.
(3 + 3 = 6)
#B. DEMOGRAPHY
#1.
Calculate Crude Birth Rate (CBR), Early Neonatal Mortality Rate (ENMR), and Infant Mortality Rate (IMR) from the given hypothetical data of the year 2011.
(2 + 2 + 2 = 6)
Number of live births in the year = 27,000
Mid-year population = 1,655,000
Deaths within first week of life = 200
Deaths of infants before first birthday = 800
#2.
Calculate Age-Specific Fertility Rate (ASFR), Total Fertility Rate (TFR), and Gross Reproduction Rate (GRR) from the following information.
(3 + 2 + 1 = 6)
Age Group (Years) | Female Population | Total Live Births |
|---|---|---|
15–19 | 36,000 | 2,000 |
20–24 | 34,500 | 8,000 |
25–29 | 30,000 | 7,000 |
30–34 | 27,000 | 4,000 |
35–39 | 21,000 | 2,000 |
40–44 | 18,000 | 1,000 |
45–49 | 16,000 | 200 |
Sex Ratio at Birth = 100/105
#3.
Hypothetical demographic data of Morang District (2010) is given below.
Calculate Crude Birth Rate, Mortality Rate, Infant Mortality Rate, and Maternal Mortality Ratio.
(2 + 2 + 2 = 6)
Total mid-year population = 570,000
Number of live births = 35,000
Deaths of infants before first birthday = 1,600
Deaths of women due to pregnancy or childbirth-related causes = 55
#4.
Hypothetical demographic data of Sunsari District is given below.
Calculate Perinatal Mortality Rate, Crude Death Rate, and General Fertility Rate.
(2 + 2 + 2 = 6)
Total mid-year population = 350,000
Total number of deaths in a year = 320
Number of live births = 35,000
Deaths of newborns within first 7 days of life = 120
Number of stillbirths = 20
Female population in reproductive age group (15–49 years) = 90,000
#5.
Calculate Total Fertility Rate (TFR) and Gross Reproduction Rate (GRR) from the following information.
(3 + 2 = 5)
Age Group (Years) | Female Population | Total Live Births |
|---|---|---|
15–19 | 26,000 | 1,500 |
20–24 | 24,500 | 7,000 |
25–29 | 22,000 | 9,000 |
30–34 | 20,500 | 4,000 |
35–39 | 18,000 | 1,800 |
40–44 | 16,000 | 500 |
45–49 | 15,500 | 200 |
Sex Ratio at Birth = 100/105
#6.
Calculate Crude Birth Rate, Neonatal Mortality Rate, and Maternal Mortality Ratio of Tankisinuwari from the given data of one year.
(2 + 2 + 2 = 6)
Total mid-year population = 272,000
Number of live births = 5,400
Deaths of newborns within first month of life = 80
Deaths of women due to pregnancy or childbirth-related complications = 18
#7.
Demographic data of an area (2010) is given below.
Calculate Cause-Specific Death Rate, Infant Mortality Rate, and Maternal Mortality Ratio.
(2 + 2 + 2 = 6)
Deaths due to diabetes = 120
Total diabetes cases in that year = 25,000
Number of live births = 35,000
Deaths of infants before first birthday = 1,100
Deaths of women due to pregnancy or childbirth-related causes = 40
#8.
Define Demography.
Enlist four major sources of demographic data.
(1 + 2 = 3)
#9.
What is Total Fertility Rate (TFR)?
Enlist any five measures of fertility.
(2.5 + 2.5 = 5)
#10.
List the different measures of mortality.
Why is mortality measurement important in medical sciences? Give any four reasons.
(3 + 2 = 5)
#C. PROBABILITY
#1.
A prospective cohort study was conducted on lung cancer among 50 exposed and 50 control participants for 5 years. Among the exposed group, 10 developed lung cancer, and among the control group, 4 developed lung cancer.
Find:
a. Probability (risk) of lung cancer among the exposed (1)
b. Probability (risk) of lung cancer in the total population (1)
(1 + 1 = 2)
#2.
A cohort study was conducted among 50 hypertensive patients and 50 normal persons for 5 years. Among them, 16 hypertensive and 5 normal individuals developed heart disease.
Find the Attributable Risk due to hypertension. (2)
#3.
In a screening test of 100 adults, 60 subjects had high blood pressure. Among them, 40 were obese and 20 had normal body weight.
Find the Relative Risk of developing hypertension among obese individuals compared to normal-weight individuals. (2)
#4.
Data from a cross-sectional survey on pollution exposure and asthma occurrence among 80 participants is given below:
Pollution Exposure | Asthma + | Asthma – |
|---|---|---|
Exposed | 10 | 40 |
Non-exposed | 2 | 48 |
a. Find the Attributable Risk (AR) of developing asthma due to pollution exposure (2)
b. Find the Odds Ratio among exposed and non-exposed (2)
#5.
Results of a cross-sectional study are shown below:
Smoking Habit | Disease + | Disease – |
|---|---|---|
Yes | 10 | 20 |
No | 5 | 45 |
Calculate Sensitivity and Specificity, and draw their inferences.
(1.5 + 1.5 = 3)
#D. NORMAL / POISSON / BINOMIAL PROBABILITY DISTRIBUTION
#1.
Among 150 students, 50 passed the last end-block examination.
Find the probability that 5 students will pass among 8 students in the next similar examination. (3)
#2.
The average number of children per family in Morang district was recorded as 2.5 in a survey.
Find the probability that a randomly selected family has one child. (3)
#3.
The average OPD visit rate is 4 for a group of people.
Find the probability that a randomly selected person has zero OPD visits. (3)
#4.
The mean weight of normally distributed under-five children in Nepal is 14 kg with a standard deviation of 3 kg.
Find the probability that a randomly selected child weighs 11 kg. (3)
#5.
Mean hemoglobin level among normally distributed children is 10.5 g/dl with a standard deviation of 3.4 g/dl.
Find the probability of having hemoglobin exactly 12 g/dl. (3)
#E. SAMPLING
#1.
What is sampling?
Illustrate the different methods of sampling techniques.
(2 + 3 = 5)
#2.
Define probability sampling.
Explain briefly the different types of probability sampling techniques.
(2 + 3 = 5)
#3.
Define non-probability sampling.
Differentiate between probability and non-probability sampling.
(1 + 4 = 5)
#4.
Define study population and sample.
Why is sampling necessary in medical research?
(2 + 3 = 5)
#5.
Define sampling frame.
Differentiate between sampling frame and study population.
(2 + 3 = 5)
#F. ESTIMATION
#1.
A cross-sectional survey conducted among 30 participants reported a mean weight of 51 kg with a standard deviation of 6 kg.
Find:
a. Standard Error (2)
b. 95% Confidence Interval (3)
(2 + 3 = 5)
#2.
Birat Medical College plans to conduct a study on the prevalence of diabetes among adults in Biratnagar Metropolitan City. A similar study in Nepal reported a prevalence of 25%.
Calculate the sample size for the study. (3)
#3.
A prospective cohort study was conducted on lung cancer among 50 exposed and 50 control subjects. Among them, 20 exposed and 10 control subjects developed lung cancer.
Find the Standard Error. (3)
#4.
The national mean weight among 30 Mountain people and 50 Hill people was recorded as 60 kg and 55 kg with standard deviations of 4 kg and 5 kg respectively.
Calculate:
a. Standard Error (2)
b. 95% Confidence Interval (3)
(2 + 3 = 5)
#5.
A cross-sectional study aimed to estimate the mean heart rate among adults.
Calculate the sample size given:
Mean heart rate = 81
Standard deviation = 5
(3)
