CA Foundation · Quantitative Aptitude · Correlation and Regression
A scatter diagram of the marks scored by 30 students in Accounting (X) and the hours they spent on social media per week (Y) shows points scattered randomly over the whole plot with no visible upward or downward trend. Which conclusion is most appropriate?
The variables are uncorrelated, with r close to zero. A random scatter with no upward or downward trend shows no linear association between the two variables. Strong positive or negative correlation would need points clustered around a rising or falling line, which is absent here.
- AThe variables are uncorrelated, with r close to zeroCorrect
- BThe variables are perfectly positively correlated
- CThe variables have a strong non-linear but positive relationship with r = 1
- DThe variables are negatively correlated with r close to -1
Explanation
A random cloud with no trend means there is no linear association, so r is near zero. Perfect correlation (r = +1 or -1) would require all points to lie exactly on a straight line. A tight negative pattern would show points falling consistently from left to right.
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