In normal distribution which have same value
**Core Concept**
In statistics, a normal distribution is a probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean. The normal distribution is characterized by its mean (μ) and standard deviation (σ), which together define the shape of the distribution.
**Why the Correct Answer is Right**
The correct answer is related to the concept of the standard deviation, which is a measure of the amount of variation or dispersion of a set of values. In a normal distribution, about 68% of the data falls within one standard deviation of the mean, about 95% falls within two standard deviations, and about 99.7% falls within three standard deviations. This means that the majority of the data points lie within a specific range, and those that lie outside of this range are considered to be outliers.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because it does not provide any information about the normal distribution.
* **Option B:** This option is incorrect because it is not related to the concept of standard deviation in a normal distribution.
* **Option C:** This option is incorrect because it is not a correct statement about the normal distribution.
**Clinical Pearl / High-Yield Fact**
In statistics, the 68-95-99.7 rule (also known as the empirical rule) is a useful concept to remember, as it provides a quick way to estimate the percentage of data points that fall within a certain range of the mean.
**Correct Answer:** D.