Question

The most important condition for sound conclusions from statistical inference is usually

that the data can be thought of as a random sample from the population of interest.
that the population distribution is exactly Normal.
that the data contain no outliers.

Answer 1

that the data can be thought of as a random sample from the population of interest.

Explanation:

Sound conclusions can be drawn from a population that is not a Normal distribution.

Outliers can affect some measures of a population; however, not all of them are greatly affected.

However if a sample cannot be thought of as a random sample, we cannot make sound conclusions. This is because if the sample is not random, then there could potentially be bias in the results.