EOC EOC Statistics and Probability 2 — Questions and Answers
Question 1: What is 'standard deviation' a measure of?
- The average value in a data set
- The middle value in a data set
- How spread out values are from the mean (Correct answer)
- The total number of data points
Correct answer: How spread out values are from the mean
Standard deviation measures how much individual data points in a set deviate or differ from the mean, indicating variability or spread.
Question 2: If two events are independent, how is the probability that both occur calculated?
- By adding their individual probabilities
- By subtracting their probabilities
- By multiplying their individual probabilities (Correct answer)
- By dividing one probability by the other
Correct answer: By multiplying their individual probabilities
For independent events, the probability that both occur equals the product of their individual probabilities: P(A and B) = P(A) × P(B).
Question 3: A scatter plot shows data points clustered closely along a line going from lower-left to upper-right. What does this indicate?
- A negative correlation
- No correlation
- A strong positive correlation (Correct answer)
- A non-linear relationship
Correct answer: A strong positive correlation
When data points cluster closely around a line that rises from left to right, it indicates a strong positive correlation between the two variables.
Question 4: What is the 'mode' of a data set?
- The average value
- The middle value
- The most frequently occurring value (Correct answer)
- The lowest value
Correct answer: The most frequently occurring value
The mode is the value that appears most often in a data set, and a data set can have one mode, multiple modes, or no mode at all.
Question 5: Which measure of central tendency is most affected by extreme outliers in a data set?
- Mode
- Median
- Mean (Correct answer)
- Range
Correct answer: Mean
The mean is most sensitive to outliers because it uses every value in its calculation, so a very large or small value can significantly shift the average.
Question 6: What does a correlation coefficient of -1 indicate?
- No relationship between variables
- A perfect positive linear relationship
- A perfect negative linear relationship (Correct answer)
- A non-linear relationship
Correct answer: A perfect negative linear relationship
A correlation coefficient of -1 indicates a perfect negative linear relationship, meaning as one variable increases, the other decreases exactly proportionally.
EOC EOC Statistics and Probability 2
What is 'standard deviation' a measure of?