Psychological Research & Statistics 20 MCQs: Descriptive & Inferential Statistics, Variables & Measurement Scales

Test your knowledge with 20 MCQs on Psychological Research & Statistics, covering Descriptive & Inferential Statistics, Variables, Constants, and Measurement Scales. Includes answers and explanations!

1. What is the primary goal of psychological research?

a) To prove theories correct
b) To explore, describe, explain, and predict behavior
c) To manipulate human behavior
d) To eliminate variables

✅ Answer: b) To explore, describe, explain, and predict behavior
💡 Explanation: Psychological research aims to understand human behavior scientifically by identifying patterns, relationships, and underlying causes.

2. Descriptive statistics primarily help in:

a) Making predictions about a population
b) Summarizing and organizing data
c) Establishing causation
d) Conducting experiments

✅ Answer: b) Summarizing and organizing data
💡 Explanation: Descriptive statistics (e.g., mean, median, mode) help in organizing and summarizing data but do not infer conclusions beyond the sample data.

3. Inferential statistics are used to:

a) Describe a data set
b) Make generalizations about a population from a sample
c) Organize raw data
d) Avoid biases in research

✅ Answer: b) Make generalizations about a population from a sample
💡 Explanation: Inferential statistics, like t-tests and ANOVA, allow researchers to draw conclusions about a larger population based on a sample.

4. A variable that can take on any value within a range is called:

a) Discrete variable
b) Dependent variable
c) Continuous variable
d) Constant

✅ Answer: c) Continuous variable
💡 Explanation: A continuous variable can assume an infinite number of values within a given range, such as height, weight, or reaction time.

5. Which of the following is an example of a nominal scale?

a) Temperature in Celsius
b) Ranking in a race
c) Gender categories
d) Age in years

✅ Answer: c) Gender categories
💡 Explanation: A nominal scale classifies data into categories without a specific order, such as gender, race, or nationality.

6. In an experiment, the variable that is manipulated by the researcher is called:

a) Dependent variable
b) Extraneous variable
c) Independent variable
d) Confounding variable

✅ Answer: c) Independent variable
💡 Explanation: The independent variable is the one researchers manipulate to observe its effects on the dependent variable.

7. The measure of central tendency most affected by extreme values is:

a) Mean
b) Median
c) Mode
d) Range

✅ Answer: a) Mean
💡 Explanation: The mean considers all values, so extreme values (outliers) can significantly affect it, making the median a better choice in skewed distributions.

8. Which measurement scale allows both ranking and equal intervals but lacks a true zero?

a) Nominal
b) Ordinal
c) Interval
d) Ratio

✅ Answer: c) Interval
💡 Explanation: The interval scale has equal intervals between values (e.g., temperature in Celsius) but lacks an absolute zero point.

9. What type of variable remains unchanged throughout a study?

a) Independent variable
b) Dependent variable
c) Constant
d) Extraneous variable

✅ Answer: c) Constant
💡 Explanation: A constant does not change during research and helps maintain controlled conditions.

10. Which of the following is an example of ordinal data?

a) Blood type categories
b) Student rankings in a class
c) Weight of an individual
d) Eye color

✅ Answer: b) Student rankings in a class
💡 Explanation: Ordinal data has a meaningful order but does not have equal intervals between values, like rankings or satisfaction levels.

11. A t-test is used to compare:

a) Three or more group means
b) The correlation between two variables
c) The means of two groups
d) Frequencies in categorical data

✅ Answer: c) The means of two groups
💡 Explanation: A t-test determines if there is a significant difference between the means of two groups.

12. The standard deviation measures:

a) The middle value in a data set
b) The most frequently occurring value
c) The spread of data from the mean
d) The sum of all values in a data set

✅ Answer: c) The spread of data from the mean
💡 Explanation: Standard deviation quantifies the dispersion of data points around the mean, indicating variability.

13. Which measure of dispersion is the simplest to calculate?

a) Variance
b) Standard deviation
c) Range
d) Mean deviation

✅ Answer: c) Range
💡 Explanation: The range is the difference between the highest and lowest values, making it the easiest dispersion measure to compute.

14. Which type of error occurs when a true null hypothesis is rejected?

a) Type I error
b) Type II error
c) Sampling error
d) Measurement error

✅ Answer: a) Type I error
💡 Explanation: A Type I error happens when the null hypothesis is incorrectly rejected, meaning a false positive result.

15. The best measure for skewed data distributions is:

a) Mean
b) Mode
c) Median
d) Variance

✅ Answer: c) Median
💡 Explanation: The median is resistant to extreme values, making it a better measure of central tendency for skewed distributions.

16. A correlation coefficient of -0.9 indicates:

a) A strong positive relationship
b) A weak negative relationship
c) A strong negative relationship
d) No relationship

✅ Answer: c) A strong negative relationship
💡 Explanation: A correlation close to -1 signifies a strong inverse relationship between two variables.

17. The primary purpose of ANOVA is to:

a) Compare two means
b) Compare three or more group means
c) Test for correlation
d) Measure dispersion

✅ Answer: b) Compare three or more group means
💡 Explanation: Analysis of Variance (ANOVA) determines whether significant differences exist among multiple group means.

18. In research, a hypothesis is:

a) A proven fact
b) A testable prediction
c) A random guess
d) A statistical method

✅ Answer: b) A testable prediction
💡 Explanation: A hypothesis is a statement that can be tested scientifically through research and experimentation.

19. Which scale has an absolute zero point?

a) Ordinal
b) Interval
c) Ratio
d) Nominal

✅ Answer: c) Ratio
💡 Explanation: The ratio scale includes an absolute zero, allowing for meaningful comparisons (e.g., weight, height, income).

20. What does a p-value of 0.05 indicate?

a) A 95% chance that the null hypothesis is true
b) A 5% probability of obtaining the observed results if the null hypothesis is true
c) A highly significant result
d) No relationship exists

✅ Answer: b) A 5% probability of obtaining the observed results if the null hypothesis is true

💡 Explanation: A p-value of 0.05 means there is a 5% chance that the results occurred due to random chance, commonly used as a significance threshold.