Functions for specifying randomly generated values

The following functions are available for specifying randomly generated values. You can enter these functions and their values in the Min and Max fields of the variable definition table or in an answer box.

Function	Format	Purpose	Example
rand	rand(range-start,range-end,exponent)	Generates a random number within a specified range, optionally rounded to a specific power of 10.	rand(10,100,1) randomly returns 10, 20, 30, ...100. The default value for exponent is 0; that is, the value returned is rounded to the nearest integer.
round	round(value,exponent)	Rounds a value to a specific power of 10.	round(1.2345,-3) returns 1.235.
sigdig	sigdig(value,exponent)	Rounds a value to a specific number of significant digits.	sigdig(1.2345,3) returns 1.23.
ifthenelse	ifthenelse(test,true_value,false_value)	Returns one of two values depending on the result of a logical test.	ifthenelse(x>y,x,y) returns x if x is larger; otherwise it returns y.

 

ifthenelse function example

 

Variable	Description
y	ifthenelse is used to produce the value 1 or 0 based on the value of x. If x is a number between 6 and 10, the value 1 is returned. If x is a number between 1 and 5, the value 0 is returned.

 

round function example

These variables are in an item to calculate the total energy required to convert a solid to a gas using heat capacity, heat of fusion, and heat of vaporization.

 

 

Variable	Description
q_1	Function n_1*6.02 is rounded to 10-1, or to the first decimal place. For example, if n_1*6.02 is equal to 12.162, the value is rounded to 12.2.
q_2	Function (m_1*4.184)/10 is rounded to 10-1, or to the first decimal place.
q_3	Function n_1*40.7 is rounded to 100, or to the first integer. For example, if n_1*40.7 is equal to 12.162, the value is rounded to 12.

 

See also: 

Random variables overview

Defining random variables

Formatting variables