Normal Distribution

Front

What is Normal Distribution?

Back

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.

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What is the mean in a normal distribution?

Back

The average of all data points, which is the center of the distribution.

Front

What is variance?

Back

A measure of how much values in a data set differ from the mean, calculated as the average of the squared differences from the mean.

Front

What is the standard deviation?

Back

The square root of the variance, representing the average distance of each data point from the mean.

Front

What does a Z-score represent?

Back

The number of standard deviations a data point is from the mean.

Front

What is the empirical rule (68-95-99.7 rule)?

Back

In a normal distribution, approximately 68% of data falls within 1 standard deviation, 95% within 2 standard deviations, and 99.7% within 3 standard deviations of the mean.

Front

How do you calculate the Z-score?

Back

Z = (X - μ) / σ, where X is the value, μ is the mean, and σ is the standard deviation.

Front

What is the significance of a Z-score of 0?

Back

A Z-score of 0 indicates that the data point is exactly at the mean.

Front

What percentage of data falls within 1 standard deviation of the mean in a normal distribution?

Back

Approximately 68%.

Front

What percentage of data falls within 2 standard deviations of the mean in a normal distribution?

Back

Approximately 95%.