Epätodennäköisyysnäyte

Epätodennäköisyysnäyte, in English referred to as an unlikely sample or improbable sample, is a statistical concept that describes a sample of data that is highly unlikely to occur if a particular null hypothesis were true. It is a fundamental concept in hypothesis testing, forming the basis for deciding whether to reject or fail to reject the null hypothesis.

When a researcher conducts a study, they typically start with a null hypothesis, which is a statement of no effect or no difference. They then collect data and analyze it. The epätodennäköisyysnäyte arises when the observed data deviates significantly from what would be expected under the null hypothesis. This deviation is quantified using a p-value, which represents the probability of observing a sample as extreme as, or more extreme than, the one collected, assuming the null hypothesis is true.

A small p-value (typically below a predetermined significance level, often 0.05) indicates that the observed sample is an epätodennäköisyysnäyte. This suggests that the null hypothesis is unlikely to be true, leading the researcher to reject it in favor of an alternative hypothesis. Conversely, a large p-value means the observed sample is not particularly unlikely under the null hypothesis, and therefore, the researcher would fail to reject it. The concept highlights the role of chance in scientific observation and the statistical reasoning used to draw conclusions from data.