This article describes the formula syntax and usage of the PROB function in Microsoft Excel.
Description
Returns the probability that values in a range are between two limits. If upper_limit is not supplied, returns the probability that values in x_range are equal to lower_limit.
Syntax
PROB(x_range, prob_range, [lower_limit], [upper_limit])
The PROB function syntax has the following arguments:

X_range Required. The range of numeric values of x with which there are associated probabilities.

Prob_range Required. A set of probabilities associated with values in x_range.

Lower_limit Optional. The lower bound on the value for which you want a probability.

Upper_limit Optional. The optional upper bound on the value for which you want a probability.
Remarks

If any value in prob_range ≤ 0 or if any value in prob_range > 1, PROB returns the #NUM! error value.

If the sum of the values in prob_range is not equal to 1, PROB returns the #NUM! error value.

If upper_limit is omitted, PROB returns the probability of being equal to lower_limit.

If x_range and prob_range contain a different number of data points, PROB returns the #N/A error value.
Example
Copy the example data in the following table, and paste it in cell A1 of a new Excel worksheet. For formulas to show results, select them, press F2, and then press Enter. If you need to, you can adjust the column widths to see all the data.
Data 

Value of x 
Probability 

0 
0.2 

1 
0.3 

2 
0.1 

3 
0.4 

Formula 
Description 
R esult 
=PROB(A3:A6,B3:B6,2) 
Probability that x is 2. 
0.1 
=PROB(A3:A6,B3:B6,1,3) 
Probability that x is between 1 and 3. 
0.8 