DA0-002 Data Analysis Practice Question
A researcher is designing an A/B test to compare two website layouts. Which TWO elements are essential for determining the required sample size?
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Statistical power
Statistical power and desired effect size are key inputs for sample size calculation.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Sample mean
Why it's wrong here
Sample mean is not known beforehand.
- ✓
Statistical power
Why this is correct
Power affects the probability of detecting an effect.
- ✗
Confidence interval width
Why it's wrong here
While related, it is not a direct input; power and effect size are standard.
- ✓
Desired effect size
Why this is correct
The minimum effect size of interest influences sample size.
- ✗
P-value
Why it's wrong here
P-value is an outcome, not an input for sample size calculation.
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