What percentage of values fall within +/- 2 standard deviations in a normal Gaussian distribution?

In a normal Gaussian distribution, also known as a bell curve, a key characteristic is how data is distributed around the mean. The empirical rule, or the 68-95-99.7 rule, states that:

• Approximately 68% of the values fall within one standard deviation (±1) of the mean.
• About 95% of the values fall within two standard deviations (±2) of the mean.

• Nearly 99.7% of the values are found within three standard deviations (±3) of the mean.

Thus, when looking for the percentage of values that fall within ±2 standard deviations, the empirical rule indicates that this entails approximately 95%. This foundational concept is crucial in fields like statistics and quality control, as it provides insights into the variability and reliability of data.

In this case, the understanding of the Gaussian distribution and the empirical rule confirms that the correct response, 95%, accurately represents the span of values located within two standard deviations of the mean in a normally distributed dataset.