CWA Data Analysis & Interpretation Techniques 2

Question 1

Overall conversion rate rose, yet every individual traffic segment's conversion rate fell. What phenomenon best explains this?

Accepted Answer

Simpson's paradox caused by a shift in traffic mix

Answer

Simpson's paradox occurs when aggregate trends reverse because the proportion of segments changed.

Question 2

Which analysis groups users by the date they first visited and tracks their behavior over subsequent weeks?

Accepted Answer

Cohort analysis

Answer

Cohort analysis compares groups sharing a common starting event over time to reveal retention patterns.

Question 3

A report shows a 40% jump in sessions on a single day with no marketing activity. What should the analyst do FIRST?

Accepted Answer

Check for anomalies such as bot traffic, tracking duplication, or a tagging change

Answer

Unexplained spikes should be validated against data-quality causes before being interpreted as real performance.

Question 4

Which metric is the most appropriate for comparing the efficiency of two campaigns with very different traffic volumes?

Accepted Answer

Conversion rate

Answer

Rate-based metrics normalize for volume, allowing fair comparison between unequal groups.

Question 5

When the mean time on page is 4 minutes but the median is 40 seconds, what does this most likely indicate?

Accepted Answer

A few extremely long sessions skew the mean upward

Answer

A mean far above the median signals a right-skewed distribution driven by outliers.

CWA - Certified Web Analyst Practice Test