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Normal Distribution Calculator

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QXL Stat Tools Tab > Distribution Fit/Calc > Distribution Calculator > Normal

Normal Distribution is a continuous probability distribution. It is characterized by a bell-shaped curve. The Normal Distribution calculator allows you to calculate the area under the normal curve.

To start the calculator, go to Statistical Tools > Distributions > Normal.

Mean and Standard Deviation

After you enter the Mean and Standard Deviation, Quantum XL will create the normal probability curve in a new Excel worksheet. The Standard Deviation must be greater than 0.

Calculate area under the curve

In order to calculate the area under the curve you will need to enter at least one cutoff point (Lower or Upper). Depending on which cutoff point you define, Quantum XL can calculate:

• Probability that X is less than or equal to cutoff point.

• Probability that X is greater than or equal to cutoff point.

• Probability that X is between two cutoff points (you will need to set both Lower and Upper cutoff points).

Select the calculation option from the Probability drop down box.

Calculated probability is graphically represented as the red area under the normal curve.