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A normal distribution can also have a negative mean. However, the standard deviation of a normal distribution is always positive – it is never negative or zero. Of course, for a normal distribution to have a negative mean, there would need to be some data points with negative values.
- Can Z be negative in normal distribution?
- How do you find a negative normal distribution?
- What happens if z-score is negative?
Can Z be negative in normal distribution?
A negative z-score reveals the raw score is below the mean average. For example, if a z-score is equal to -2, it is 2 standard deviations below the mean.
How do you find a negative normal distribution?
The standard normal is a symmetric distribution. The area under the curve to the left of the Y-axis is same as to the right. Therefore to find a negative Z-score from a positive standard normal table, find the value corresponding to the required area under the curve and take the negative of the value.
What happens if z-score is negative?
A positive z-score says the data point is above average. A negative z-score says the data point is below average. A z-score close to 0 says the data point is close to average. A data point can be considered unusual if its z-score is above 3 or below −3 .
