Answer:
D. n1 and n2 can be of different sizes
Step-by-step explanation:
When we are trying to develop interval estimate for difference between two populations, we first select two samples from these populations. We get the interval using the required statistic.
These are:
- Sample size of both populations. Which are n1 and n2 respectively.
- then the Sample mean of two populations
- sample standard deviation.
The samples of different sample sizes can be used and we are not obligated to make use of the same sample size.