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What is Quota Sampling?
Grade Level:
Class 12
AI/ML, Physics, Biotechnology, FinTech, EVs, Space Technology, Climate Science, Blockchain, Medicine, Engineering, Law, Economics
Definition
What is it?
Quota sampling is a non-probability sampling method where researchers divide a population into specific groups (quotas) based on certain characteristics like age, gender, or location. They then select a fixed number of individuals from each group until the pre-determined quota for that group is met, without using random selection.
Simple Example
Quick Example
Imagine a snack company wants to know which new chip flavour teenagers in your city like most. Instead of picking students randomly, they decide to survey 50 boys and 50 girls from different schools. They keep surveying until they have exactly 50 boys and 50 girls, making sure both groups are equally represented.
Worked Example
Step-by-Step
Let's say a mobile app company wants feedback on a new feature from 200 users. They decide to use quota sampling based on user age groups:
1. **Identify Quotas:** They decide they need 40% feedback from users aged 18-25, 30% from 26-35, and 30% from 36-45.
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2. **Calculate Numbers:** For 200 users:
* 18-25 age group: 40% of 200 = 0.40 * 200 = 80 users
* 26-35 age group: 30% of 200 = 0.30 * 200 = 60 users
* 36-45 age group: 30% of 200 = 0.30 * 200 = 60 users
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3. **Start Sampling:** The researchers go out and find users. They might approach people in malls, online forums, or through social media.
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4. **Fill Quotas:** They keep interviewing users until they have exactly 80 users from the 18-25 group, 60 from the 26-35 group, and 60 from the 36-45 group.
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5. **Stop:** Once all quotas are filled, they stop collecting data, even if more people are willing to give feedback.
Answer: The company successfully collected feedback from 200 users, ensuring specific numbers from each age group.
Why It Matters
Quota sampling is crucial in market research, public opinion polls, and social sciences because it helps ensure specific groups are represented in a survey. Understanding this method is vital for careers in data science, marketing analytics, and even for engineers designing user-friendly products, as it helps them gather targeted feedback efficiently.
Common Mistakes
MISTAKE: Thinking quota sampling is random. | CORRECTION: It's non-random. Researchers pick people until the quota is met, not through chance.
MISTAKE: Confusing quotas with stratified sampling. | CORRECTION: In stratified sampling, individuals are chosen randomly from each group. In quota sampling, they are chosen non-randomly.
MISTAKE: Believing quota sampling perfectly represents the whole population. | CORRECTION: While it ensures representation of specific groups, the non-random selection can lead to bias, meaning it might not fully reflect everyone.
Practice Questions
Try It Yourself
QUESTION: A researcher wants to survey 100 people about their favourite car brand, ensuring 50 men and 50 women are included. What type of sampling is this? | ANSWER: Quota sampling.
QUESTION: A political party wants to survey 500 voters: 200 from urban areas, 150 from semi-urban, and 150 from rural areas. They will approach people in these areas until the numbers are met. Is this a probability or non-probability sampling method? Explain briefly. | ANSWER: Non-probability sampling. Because individuals are not selected randomly; the researchers choose them until the pre-set quotas for each area are filled.
QUESTION: A new online education platform wants feedback from 300 students. They decide to get feedback from 100 students from Class 10, 100 from Class 11, and 100 from Class 12. If they approach students at coaching centres and schools until they get these numbers, what is a potential drawback of this sampling method? | ANSWER: A potential drawback is selection bias. Students at coaching centres or specific schools might not represent all students in those classes (e.g., they might be more academically inclined or from a certain socio-economic background), leading to feedback that doesn't reflect the general student population.
MCQ
Quick Quiz
Which of the following is a characteristic of quota sampling?
Every member of the population has an equal chance of being selected.
It involves randomly selecting individuals from pre-defined groups.
Researchers select individuals non-randomly to meet pre-set numbers for specific groups.
It requires a complete list of the entire population.
The Correct Answer Is:
C
Quota sampling involves researchers intentionally choosing individuals to fill specific 'quotas' for different groups, rather than using random selection. Options A, B, and D describe probability sampling methods or requirements not central to quota sampling.
Real World Connection
In the Real World
In India, companies like Zomato or Swiggy might use quota sampling when testing new app features or delivery options. They might want feedback from 100 users in Delhi, 100 in Mumbai, and 50 in a Tier 2 city like Lucknow, making sure to get a specific number of responses from each location to understand regional preferences before a full launch.
Key Vocabulary
Key Terms
POPULATION: The entire group of individuals that a researcher is interested in studying. | SAMPLE: A smaller, representative group chosen from the population for study. | QUOTA: A pre-determined number or proportion of individuals from a specific subgroup that needs to be included in a sample. | NON-PROBABILITY SAMPLING: A sampling method where not every member of the population has an equal chance of being selected.
What's Next
What to Learn Next
Now that you understand quota sampling, explore 'Stratified Sampling'. It's another method that divides populations into groups, but uses random selection within those groups, which is a key difference you should know!
