Theoretical Distribution

Concept:The total area under a normal probability density curve is 1, and it is symmetric about the mean $\mu$.Explanation:For a standard normal distribution, the area from $-\infty$ to $\mu$ equals the area from $\mu$ to $\infty$, each being 0.5.Option C is incorrect because the total area from $-\infty$ to $\infty$ is 1, not 0.50.Options A and B are both individually correct statements.Answer:Both (a) and (b) are correct.