Online Test — Correlation
15 Questions • 15 min • Chapter MCQ
15:00
Question 1 of 15
Correlation measures the ____ between two variables.
Sum
Relationship
Average
Frequency
Explanation: Correlation measures the relationship between two variables.
Question 2 of 15
When both variables move in the same direction, correlation is:
Positive
Negative
Zero
Perfect negative
Explanation: Same-direction movement is positive correlation.
Question 3 of 15
Price and demand usually show ____ correlation.
Positive
Negative
Zero
Perfect positive
Explanation: As price rises, demand falls — negative correlation.
Question 4 of 15
A graph plotting pairs of values as dots is a:
Histogram
Scatter diagram
Pie chart
Ogive
Explanation: Plotting pairs as dots gives a scatter diagram.
Question 5 of 15
On a scatter diagram, dots falling from left to right show:
Positive correlation
Negative correlation
No correlation
Perfect positive
Explanation: Falling dots show negative correlation.
Question 6 of 15
Karl Pearson's coefficient r always lies between:
0 and 1
−1 and +1
−10 and +10
1 and 100
Explanation: r ranges from −1 to +1.
Question 7 of 15
r = +1 means:
Perfect positive correlation
Perfect negative correlation
No correlation
Weak correlation
Explanation: r = +1 is perfect positive correlation.
Question 8 of 15
r = 0 means:
Perfect correlation
No correlation
Strong correlation
Negative correlation
Explanation: r = 0 means no correlation.
Question 9 of 15
Pearson's formula uses deviations from the:
Mode
Mean
Median
Range
Explanation: dx and dy are deviations from the mean.
Question 10 of 15
If Σ(dx·dy)=300, Σdx²=100, Σdy²=900, then r equals:
1
0.5
0
−1
Explanation: r = 300 ÷ √(100×900) = 300 ÷ 300 = 1.
Question 11 of 15
Spearman's rank correlation is used for:
Ranked or qualitative data
Only exact measurements
Pie charts
Time series only
Explanation: Spearman's R suits ranked/qualitative data.
Question 12 of 15
In Spearman's formula, D stands for the:
Difference between the two ranks
Mean
Total
Frequency
Explanation: D is the difference between the two ranks of an item.
Question 13 of 15
Spearman's R = 1 − [6ΣD² ÷ N(N²−1)]. For ΣD²=4, N=5, R is:
0.8
0.2
−0.8
1
Explanation: R = 1 − (6×4)/(5×24) = 1 − 24/120 = 1 − 0.2 = 0.8.
Question 14 of 15
A correlation coefficient close to 0 indicates:
Strong correlation
Weak or no correlation
Perfect correlation
Causation
Explanation: Values near 0 mean weak or no correlation.
Question 15 of 15
The statement 'correlation is not causation' warns that:
A third factor may cause both variables
r is always wrong
Ranks cannot be used
Scatter diagrams are useless
Explanation: Two correlated variables may both be driven by a hidden third factor.