Step 1: Understanding the Concept:
A simple hypothesis is one that completely specifies the distribution of the population.
This means it specifies both the form (e.g., normal) and all the parameters (mean, variance, etc.) exactly.
Step 2: Analyzing the Options:
• (A) Specifies only the mean, not the variance.
The distribution is not completely specified. So, it is a composite hypothesis.
• (B) Specifies both the mean (2.5) and the variance (15.6) exactly.
The distribution is completely specified. So, it is a simple hypothesis.
• (C) Specifies only the variance, not the mean.
The distribution is not completely specified. So, it is a composite hypothesis.
• (D) Specifies the mean (2.5) and a range for the variance (greater than 1.56).
The variance is not specified exactly. So, it is a composite hypothesis.
Step 3: Final Answer:
Therefore, option (B) is correct.