Scientific Research Methods Quiz

Grade 12 · Science · Quiz

Test your ability to evaluate experimental design, interpret data, and apply principles of scientific reasoning.

Questions

1. A researcher randomly assigns 200 participants to a drug group or a placebo group without the participants knowing which they received. This design is called a:

   1. Cohort study
   2. Case-control study
   3. Single-blind randomized controlled trial
   4. Double-blind experiment
   Show answer

   Answer: Single-blind randomized controlled trial

   A single-blind RCT hides treatment assignment from participants but not from the researcher; a double-blind design hides it from both. This design has participants unaware, so it is single-blind.

2. Which measure of central tendency is most affected by extreme outliers in a dataset?

   1. Mode
   2. Median
   3. Mean
   4. Range
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   Answer: Mean

   The mean is calculated using all values, so a single extreme outlier can shift it dramatically; the median (middle value) and mode (most frequent) are resistant to outliers.

3. Occam's Razor is a principle in scientific reasoning that advises:

   1. Never discard a hypothesis until it is tested 100 times
   2. Prefer the explanation with the fewest unnecessary assumptions
   3. All variables must be tested independently
   4. Experiments must be replicated in at least 3 countries
   Show answer

   Answer: Prefer the explanation with the fewest unnecessary assumptions

   Occam's Razor (law of parsimony) states that among competing hypotheses, the one with the fewest and most reasonable assumptions should be preferred, all else being equal.

4. What is the primary purpose of a control group in an experiment?

   1. To receive the highest dose of the independent variable
   2. To provide a baseline against which the experimental group is compared
   3. To be composed of the healthiest participants
   4. To test a different hypothesis simultaneously
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   Answer: To provide a baseline against which the experimental group is compared

   The control group receives no treatment (or a placebo); comparing it to the experimental group isolates the effect of the independent variable from all other factors.

5. A standard deviation value close to zero indicates that data points are:

   1. Widely spread around the mean
   2. Clustered closely around the mean
   3. Heavily skewed to the right
   4. Normally distributed
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   Answer: Clustered closely around the mean

   Standard deviation measures average distance from the mean; a low SD means data points are tightly grouped around the mean, indicating low variability.

6. Which of the following is an example of qualitative data?

   1. The mass of a sample in grams
   2. A participant's description of their pain level in words
   3. The temperature of a solution in Celsius
   4. The number of bacterial colonies on a plate
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   Answer: A participant's description of their pain level in words

   Qualitative data describes attributes or categories in words (e.g., color, pain descriptions, opinions); quantitative data is numerical and measurable.

7. A hypothesis that cannot be falsified by any possible experiment is considered scientifically strong.

   Show answer

   Answer: False

   Unfalsifiability is a weakness, not a strength — Karl Popper established that scientific claims must be falsifiable; claims that cannot be disproven are outside the domain of science.

8. The range of values within which the true population parameter is estimated to lie, with a specified level of confidence, is called a confidence _____.

   Show answer

   Answer: interval

   A 95% confidence interval means that if the experiment were repeated many times, 95% of calculated intervals would contain the true population parameter.

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