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)
X_range is the range of numeric values of x with which there are associated probabilities.
Prob_range is a set of probabilities associated with values in x_range.
Lower_limit is the lower bound on the value for which you want a probability.
Upper_limit is 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
The example may be easier to understand if you copy it to a blank worksheet.
How to copy an example
 Create a blank workbook or worksheet.
 Select the example in the Help topic.
Note Do not select the row or column headers.
Selecting an example from Help
 Press CTRL+C.
 In the worksheet, select cell A1, and press CTRL+V.
 To switch between viewing the results and viewing the formulas that return the results, press CTRL+` (grave accent), or on the Formulas tab, in the Formula Auditing group, click the Show Formulas button.

A 
B 
x 
Probability 
0 
0.2 
1 
0.3 
2 
0.1 
3 
0.4 
Formula 
Description (Result) 
=PROB(A2:A5,B2:B5,2) 
Probability that x is 2 (0.1) 
=PROB(A2:A5,B2:B5,1,3) 
Probability that x is between 1 and 3 (0.8) 
