INI-CET 2025 — Community Medicine
18 Previous Year Questions with Answers & Explanations
What is the minimum age at which a woman can provide valid consent for a Medical Termination of Pregnancy (MTP) in India?
In a village of 100 children, 10 children have a past history of measles (i.e., they are not at risk now), 20 new cases of measles were reported this year. What is the incidence of measles in this population for the year?
Match the following: Vector/agent : 1. Louse - 2. Tick - 3. Mite - 4. Poxvirus Diseases caused : A. Epidemic typhus - B. Rocky Mounted Spotted Fever (RMSF) - C. Scrub typhus - D. Molluscum contagiosum
According to WHO, which rapid molecular test is recommended as the initial diagnostic investigation for tuberculosis (TB) spine?
According to NPCBVI, blindness is defined as:
In a given population: - less than 15 years: 6000 - 15 to 64 years: 12000 - 65 years and above: 2000 Calculate the dependency ratio.
In a study done in a hospital, patients were categorized into three groups based on disease prevalence (Low, Medium, High), and individuals were then randomly selected from each group. What type of sampling is this?
In statistics, centiles and quartiles are considered as:
Which of the following is incorrectly matched with respect to the statistical parameter?
In a Primary Health Centre (PHC), a study was done on diabetic patients. Mean weight was recorded before and after 6 months of dietary intervention. Which statistical test should be used to determine significance?
INI-CET 2025 - Community Medicine INI-CET Practice Questions and MCQs
Question 1: What is the minimum age at which a woman can provide valid consent for a Medical Termination of Pregnancy (MTP) in India?
- A. 18 years (Correct Answer)
- B. 16 years
- C. 25 years
- D. 20 years
Explanation: **18 years** - In India, the legally prescribed **age of majority** for granting consent for medical procedures, including the **Medical Termination of Pregnancy (MTP)**, is **18 years**. - If the woman has attained 18 years, she alone can provide valid consent, as per Section 3(4)(a) of the **MTP Act, 1971** (as amended). *16 years* - While 16 years is a relevant age for sexual consent under the **POCSO Act**, it is not the minimum age for providing **medical consent** for MTP. - If the woman is below 18 years, her consent is not considered valid; instead, the consent of her **guardian** or **parent** is legally required for the procedure. *25 years* - This age is significantly above the required **age of majority (18 years)**; a 25-year-old woman provides her own independent and valid consent. - There is no legal provision under the MTP Act that specifically mandates the age of 25 for consent; the requirement is based only on attaining **adulthood**. *20 years* - This age is higher than the minimum legal requirement of **18 years** for giving consent. - A 20-year-old woman is legally competent to decide on her **MTP** independently without requiring parental or guardian consent.
Question 2: In a village of 100 children, 10 children have a past history of measles (i.e., they are not at risk now), 20 new cases of measles were reported this year. What is the incidence of measles in this population for the year?
- A. 22.22 % (Correct Answer)
- B. 10 %
- C. 30 %
- D. 20 %
Explanation: ***22.22 %*** - Incidence is calculated as the ratio of **new cases** (20) to the **population at risk** (susceptible population) over the specified period. - The **population at risk** is the total population (100) minus those who are already immune (10), making the denominator 90. Incidence = (20/90) × 100 = **22.22 %**. *20 %* - This result is obtained by incorrectly using the **total population** (100) as the denominator (20/100 × 100), ignoring the already immune group. - Using the total population in the denominator leads to an underestimate of the true **attack rate** or incidence among the susceptible group. *10 %* - This figure represents the proportion of children who had suffered from measles in the past (10/100), reflecting a form of **past prevalence**, not incidence. - Incidence focuses exclusively on the **new cases** that developed within the year. *30 %* - This percentage represents the **cumulative prevalence** at the end of the year, including both old (10) and new (20) cases, divided by the total population (30/100). - Incidence requires the denominator to be the **population at risk** (those who could develop the disease), not the total population.
Question 3: Match the following: Vector/agent : 1. Louse - 2. Tick - 3. Mite - 4. Poxvirus Diseases caused : A. Epidemic typhus - B. Rocky Mounted Spotted Fever (RMSF) - C. Scrub typhus - D. Molluscum contagiosum
- A. 1-B, 2-A, 3-C, 4-D
- B. 1-D, 2-B, 3-C, 4-A
- C. 1-C, 2-B, 3-A, 4-D
- D. 1-A, 2-B, 3-C, 4-D (Correct Answer)
Explanation: ***1-A, 2-B, 3-C, 4-D*** - **1-A (Louse - Epidemic typhus):** Epidemic typhus is caused by *Rickettsia prowazekii*, transmitted to humans via the bite or feces of the **human body louse** (*Pediculus humanus corporis*). This is a classic louse-borne rickettsial disease. - **2-B (Tick - Rocky Mountain Spotted Fever):** RMSF is caused by *Rickettsia rickettsii* and transmitted by **hard ticks**, primarily *Dermacentor* species. It is the most severe tick-borne rickettsial illness in the United States. - **3-C (Mite - Scrub typhus):** Scrub typhus is caused by *Orientia tsutsugamushi*, transmitted by the bite of infected **larval mites** (chiggers) of the *Leptotrombidium* genus. It is endemic in the Asia-Pacific region. - **4-D (Poxvirus - Molluscum contagiosum):** Molluscum contagiosum is a benign viral skin infection caused by the **Molluscum contagiosum virus**, a member of the Poxviridae family. It spreads through direct contact, not via arthropod vectors. *1-B, 2-A, 3-C, 4-D* - The match **1-B** is incorrect: **Louse** transmits **Epidemic typhus (A)**, not Rocky Mountain Spotted Fever (B), which is tick-borne. - The match **2-A** is incorrect: **Tick** transmits **Rocky Mountain Spotted Fever (B)**, not Epidemic typhus (A), which is louse-borne. *1-D, 2-B, 3-C, 4-A* - The match **1-D** is incorrect: **Louse** is an arthropod vector for **Epidemic typhus (A)**, while **Molluscum contagiosum (D)** is a viral disease spread by direct contact, not lice. - The match **4-A** is incorrect: **Poxvirus** causes **Molluscum contagiosum (D)**, while **Epidemic typhus (A)** is a rickettsial infection transmitted by lice, not a poxvirus disease. *1-C, 2-B, 3-A, 4-D* - The match **1-C** is incorrect: **Louse** transmits **Epidemic typhus (A)**, not **Scrub typhus (C)**, which is transmitted by larval mites. - The match **3-A** is incorrect: **Mites** transmit **Scrub typhus (C)**, not **Epidemic typhus (A)**, which is a louse-borne disease.
Question 4: According to WHO, which rapid molecular test is recommended as the initial diagnostic investigation for tuberculosis (TB) spine?
- A. CBNAAT (Correct Answer)
- B. X-ray
- C. CT scan
- D. Culture and sensitivity
Explanation: ***CBNAAT*** - The **WHO** strongly recommends **CBNAAT (GeneXpert or Truenat)** as the **initial rapid molecular diagnostic test** for extrapulmonary TB (EPTB), including **TB spine (Pott's disease)**, due to its rapid turnaround time and high sensitivity. - CBNAAT simultaneously detects **Mycobacterium tuberculosis** DNA and identifies resistance to **Rifampicin**, providing critical information for prompt treatment initiation, typically within 2 hours. - This rapid molecular test is preferred over traditional methods for initial diagnosis to enable early treatment decisions. *Incorrect: X-ray* - X-rays are imaging studies useful for detecting features like **vertebral destruction**, **paraspinal shadow**, and collapse leading to **gibbus deformity**, but they are not molecular diagnostic tests. - While X-rays are included in the diagnostic workup, they cannot confirm the presence of the organism or detect drug resistance, which is why they are not the WHO-recommended initial molecular test. *Incorrect: CT scan* - CT scans offer superior visualization of subtle bony changes, extent of destruction, and delineating **paraspinal cold abscesses**, often used for staging and guiding intervention. - Like X-ray, CT is an **imaging modality** that assists in identifying structural changes but is not a molecular diagnostic test and cannot provide microbiological confirmation or drug resistance information. *Incorrect: Culture and sensitivity* - **Culture (e.g., Lowenstein-Jensen, MGIT)** is considered the **gold standard** for definitive diagnosis and comprehensive Drug Susceptibility Testing (DST). - However, culture results are slow (taking 4–8 weeks), which delays crucial management decisions, leading the WHO to prioritize **rapid molecular tests** like CBNAAT for **initial diagnosis** over culture, though culture remains important for comprehensive DST.
Question 5: According to NPCBVI, blindness is defined as:
- A. Corrected visual acuity 6/60 in better eye
- B. Corrected visual acuity 3/60 in better eye
- C. Presenting visual acuity < 3/60 in better eye (Correct Answer)
- D. Presenting visual acuity 6/60 in better eye
Explanation: ***Presenting visual acuity < 3/60 in better eye*** - According to the **NPCBVI (National Programme for Control of Blindness and Visual Impairment)**, blindness is defined as **presenting visual acuity of less than 3/60** or visual field loss less than 10 degrees in the better eye. - **Presenting visual acuity** is defined as the visual acuity measured with the person's current spectacle correction (if any) or without correction. - This definition helps capture the true burden of vision loss in the community, including those who lack access to or compliance with corrective measures. *Corrected visual acuity 3/60 in better eye* - Using **"corrected visual acuity"** implies measurement taken with the best possible spectacle or contact lens correction, which is used for defining vision impairment according to **WHO standards**, but not the specific NPCBVI definition for blindness status in India. - The current NPCBVI definition uses **presenting acuity** to better reflect the functional vision status in real-world conditions. *Presenting visual acuity 6/60 in better eye* - A visual acuity of 6/60 (or less than 6/18 down to 6/60) in the better eye falls under the category of **Severe Visual Impairment** or low vision, but not clinical blindness, according to NPCBVI and WHO definitions. - The cut-off for clinical blindness is significantly lower, which is **less than 3/60**. *Corrected visual acuity 6/60 in better eye* - This measurement, regardless of whether it is presenting or corrected, falls into the category of **Visual Impairment** (low vision), specifically severe visual impairment (WHO Category 2). - The defining threshold for clinical blindness is acuity worse than 3/60, not 6/60.
Question 6: In a given population: - less than 15 years: 6000 - 15 to 64 years: 12000 - 65 years and above: 2000 Calculate the dependency ratio.
- A. 50 %
- B. 75 %
- C. 33 %
- D. 66 % (Correct Answer)
Explanation: ***66 %*** - The **Dependency Ratio** measures the ratio of the economically dependent population to the economically productive population, usually expressed as a percentage. - **Dependent Population** (aged < 15 and ≥ 65): 6000 + 2000 = **8000** - **Productive Population** (aged 15-64): **12000** - **Dependency Ratio**: (8000 / 12000) × 100 = **66.67%** (rounded to 66%) *Incorrect: 33 %* - This figure is significantly lower than the true ratio and results from calculating the ratio of the dependent population to the **total population**, which is not the standard definition of the Dependency Ratio. - 33.3% represents the dependent population (8000) as a proportion of the total population (20000), not the dependency burden on the working population. *Incorrect: 50 %* - This result is obtained if only the young dependent group is used in the numerator (Young Dependency Ratio = 6000 / 12000 = **50%**). - However, the total Dependency Ratio must account for **both young and old dependents** to accurately reflect the economic burden. *Incorrect: 75 %* - Obtaining 75% would require the dependent population to be 9000 (i.e., 9000 / 12000), which is higher than the actual 8000 dependents. - This option represents an overestimation of the dependent burden on the working population.
Question 7: In a study done in a hospital, patients were categorized into three groups based on disease prevalence (Low, Medium, High), and individuals were then randomly selected from each group. What type of sampling is this?
- A. Systematic random sampling
- B. Cluster random sampling
- C. Simple random sampling
- D. Stratified random sampling (Correct Answer)
Explanation: ***Correct: Stratified random sampling*** - This method involves dividing the population into non-overlapping subgroups (**strata**) based on a characteristic (here, disease prevalence: Low, Medium, High). - Subsequently, a **simple random sample** is drawn from *each* stratum independently to ensure representation from all groups. - This ensures that each subgroup is adequately represented in the final sample, making it ideal when the population has distinct subgroups. *Incorrect: Simple random sampling* - Every individual in the entire population has an equal and independent chance of being selected. - It does not involve dividing the population into specific subgroups or categories before selection. - This method may underrepresent or overrepresent certain subgroups by chance. *Incorrect: Systematic random sampling* - This involves selecting every *k*th element after a random start point, where *k* is the sampling interval (Population Size/Sample Size). - Like simple random sampling, it does not involve creating predefined strata based on characteristics like disease prevalence. - It's a simpler alternative to simple random sampling but doesn't ensure representation of specific subgroups. *Incorrect: Cluster random sampling* - The population is divided into natural groupings (**clusters**), such as geographical areas or schools. - Unlike stratification, entire clusters are randomly selected, and *all* individuals within the selected clusters (or a random sample thereof) are included in the study. - This differs from stratified sampling where we sample from ALL strata; in cluster sampling, we sample only SOME clusters.
Question 8: In statistics, centiles and quartiles are considered as:
- A. Measures of dispersion
- B. Measures of central tendency
- C. Measures of location/position (Correct Answer)
- D. Measures of correlation
Explanation: ***Measures of location/position***- Centiles (or **percentiles**) and **quartiles** are statistics that divide the data distribution into equal parts, indicating where a particular value stands relative to the rest of the data.- They are also known as **quantiles**, used to describe the location of specific data points within the distribution rather than summarizing the center or spread.*Measures of central tendency*- These statistics aim to describe the typical or **central value** of a dataset (e.g., **Mean**, **Median**, **Mode**).- While the median is technically the second quartile (**Q2**) and the 50th centile, the classifications of centiles and quartiles collectively are broader—measures of position.*Measures of dispersion*- These measures quantify the **spread** or **variability** of the data around the central value (e.g., **Standard Deviation**, **Variance**, Range).- Although quartiles are essential for calculating the **Interquartile Range (IQR)**, which is a measure of dispersion, the quartiles themselves define points of position.*Measures of correlation*- Correlation measures describe the **linear relationship** or association between **two variables** (e.g., Correlation Coefficient, R-value).- They are used in bivariate analysis and have no role in describing the position or central value of a single dataset.
Question 9: Which of the following is incorrectly matched with respect to the statistical parameter?
- A. Moments - Skewness
- B. Standard error - Variation
- C. Mean, median - Dispersion (Correct Answer)
- D. Correlation coefficient - Relationship
Explanation: ***Mean, median - Dispersion*** - This statement is **incorrect** because the **mean** and **median** are measures of **central tendency** (location) of a distribution, not dispersion. - Measures of dispersion quantify the spread of data, such as **standard deviation**, range, and interquartile range. ***Standard error - Variation*** - **Standard error** is a measure of the **variation** (or dispersion) of sample means around the true population mean, making this a correct match. - Specifically, it estimates how much the sample mean is likely to deviate from the population mean. ***Correlation coefficient - Relationship*** - The **correlation coefficient** (e.g., Pearson's r) measures the **strength and direction of the linear relationship** between two variables, making this a correct match. - Its value ranges from -1 (perfect negative relationship) to +1 (perfect positive relationship). ***Moments - Skewness*** - **Moments** are specific mathematical calculations used to describe the shape and characteristics of a distribution; the **third moment** is specifically used to calculate **skewness**. - **Skewness** describes the asymmetry of the distribution (whether it leans left or right), and the third moment helps quantify this.
Question 10: In a Primary Health Centre (PHC), a study was done on diabetic patients. Mean weight was recorded before and after 6 months of dietary intervention. Which statistical test should be used to determine significance?
- A. Chi-square test
- B. Unpaired t-test
- C. Paired t-test (Correct Answer)
- D. ANOVA
Explanation: ***Paired t-test*** - This test is appropriate for comparing the means of **two related samples** or measurements taken from the **same subjects** at two different time points (before and after intervention). - The study involves recording the mean weight of the *same* diabetic patients before and after a 6-month dietary intervention, making the samples dependent (paired). *Unpaired t-test* - The unpaired t-test (or Student's t-test) is used to compare the means of **two independent (unrelated) groups** (e.g., comparing the mean weight of patients in Group A vs. Group B). - It is unsuitable here because the measurements are taken from the same set of individuals, meaning the data points are related, not independent. *ANOVA* - **Analysis of Variance (ANOVA)** is used to compare the means of **three or more** independent groups (e.g., comparing mean weight across three different regions). - It is used when there are multiple levels of a factor or multiple independent variables, which is not the case when comparing two time points. *Chi-square test* - The Chi-square test is primarily used to analyze **categorical data** (frequencies or proportions) to determine if there is a significant association between two variables (e.g., relationship between gender and diabetes status). - It is unsuitable for comparing numerical values like mean weight measurements, which are continuous data.