Normal Distribution & Confidence Intervals

Front

What is the standard deviation of a normal distribution if the variance is 16?

Back

4

Front

What does the standard deviation measure on a normal distribution?

Back

The spread of data from the mean

Front

If the mean of a standard deviation is 25 and the variance is 9, what percentage of values are greater than 21?

Back

90.8

Front

What is the formula to work out the z value for a normal distribution?

Back

Front

What is the z value for a 95% confidence interval in a standard normal distribution?

Back

1.96

Front

What is a 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.

Front

What is variance in a normal distribution?

Back

A measure of how far a set of numbers are spread out from their average value.

Front

How do you calculate the variance from the standard deviation?

Back

Variance is the square of the standard deviation.

Front

What is the empirical rule in statistics?

Back

In a normal distribution, approximately 68% of the data falls within one standard deviation of the mean, 95% within two standard deviations, and 99.7% within three standard deviations.

Front

What does a z-score represent?

Back

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