The characteristics of a normal distribution include:
1. Symmetry: The distribution is symmetric around its mean, with equal probabilities of values occurring on either side of the mean.
2. Bell-shaped curve: The distribution forms a bell-shaped curve, with the highest frequency of values occurring at the mean and gradually decreasing as values move away from the mean.
3. Mean, median, and mode are equal: The mean, median, and mode of a normal distribution are all equal and located at the center of the distribution.
4. Continuous and unimodal: The distribution is continuous, meaning that it can take any value within a certain range. It is also unimodal, with a single peak at the mean.
5. Standard deviation determines spread: The spread of the distribution is determined by the standard deviation. A smaller standard deviation indicates a narrower and taller curve, while a larger standard deviation indicates a wider and flatter curve.
6. Empirical Rule: The empirical rule states that approximately 68% of the data falls within one standard deviation of the mean, 95% falls within two standard deviations, and 99.7% falls within three standard deviations.
7. Z-scores: Z-scores are used to standardize values in a normal distribution, allowing for comparison and calculation of probabilities.
8. Central Limit Theorem: The central limit theorem states that the distribution of sample means from a population will be approximately normally distributed, regardless of the shape of the population distribution, as long as the sample size is sufficiently large.
These characteristics make the normal distribution a widely used and important concept in statistics and probability theory.