Normal Distribution

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 mean is the average of all data points in a distribution, representing the center of the distribution.

The standard deviation measures the amount of variation or dispersion of a set of values. In a normal distribution, it determines the width of the curve.

The empirical rule states that for a normal distribution, approximately 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.

68%.

95%.

99.7%.

34%.

It means that the data point is higher than the average value and falls within the upper 34% of the distribution.

The z-score is calculated using the formula: z = (X - μ) / σ, where X is the data point, μ is the mean, and σ is the standard deviation.