Keys:

Display:

(In RPN mode)

 

S 

  

  D

value

  

Description:

Starts the initialization routine.Stores 55 for the mean.

Stores 15.3 for the standard deviation. Starts the distribution program and prompts for X.

Enters 90 for X and calculates Q(X).

Thus, we would expect that only about 1 percent of the students would do better than score 90.

Keys:

Display:

(In RPN mode)

 

I 

  





  

Description:

Starts the inverse routine.Stores 0.1 (10 percent) in Q(X) and calculates X.Resumes the inverse routine.

Stores 0.8 (100 percent minus 20 percent) in Q(X) and calculates X.

Grouped Standard Deviation

The standard deviation of grouped data, Sxy, is the standard deviation of data points x1, x2, ... , xn, occurring at positive integer frequencies f1, f2, ... , fn.

 

∑ x 2f −

(∑ x f )2

 

 

i i

 

 

∑fi

 

i i

 

 

 

 

Sxg

=

 

) − 1

 

(∑fi

16-18Statistics Programs