In a normal distribution, what percentage of the data lies within one Standard…
2025
In a normal distribution, what percentage of the data lies within one Standard deviation from the Mean ?
- A.
68%
- B.
95%
- C.
99.7%
- D.
50%
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Show answer & explanation
Correct answer: A
To determine the percentage of data lying within one standard deviation of the mean in a normal distribution, we refer to the Empirical Rule (also known as the 68-95-99.7 rule).
Analysis of the Empirical Rule
The Empirical Rule provides a standardized way to understand the spread of data in a normal distribution:
Within one standard deviation (±1σ): Approximately 68% of the data lies within one standard deviation from the mean.
Within two standard deviations (±2σ): Approximately 95% of the data lies within two standard deviations from the mean.
Within three standard deviations (±3σ): Approximately 99.7% of the data lies within three standard deviations from the mean.