Thread: standard deviation program

Standard Deviation



Write a program that can calculate the standard deviation of a set of numbers, which were entered from the keyboard at the run time.

The standard deviation was defined in the URL: Standard deviation - Wikipedia, the free encyclopedia .

For calculating variance, use the formula III - On-line algorithm listed at: Algorithms for calculating variance - Wikipedia, the free encyclopedia



Use the following data:



Set 1


Set 2


Set 3


Set 4

11.2


1


8


5

1.3


2


25


6

2.4


3


7


8

8.5


4


5


9

7.6


5


8




3.7


6


3




4.8


7


10




6.9


8


12




5.0


9


9




9.1


10









Required outputs:

*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*

Result:

How many numbers have been read from the data file?

Sum: of the numbers

Mean: of the numbers

Variance: of the numbers

Standard Deviation: of the numbers



*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*


Set 1 Set 2 Set 3 Set 4
Number of entered values 10 10 9 4
Sum 60.5 55 87 28
Mean 6.05 5.5 9.67 7
Variance 9.89 9.17 40 3.33
Standard Deviation 3.15 3.03 6.32 1.83





can someone teach me how to start and do with this please, i get lost with the problem and dont know what do do

Well, first of all, since you've said in your problem you will be reading the data in through a file it would probably be best writing the part of the program which loads the file and extracts the data from it. Once you've done that then calculating the standard deviation and variance should be a breeze.

On that basis, how are the numbers in your file going to be arranged (assuming you are using a text based file)? What will you use to separate them? Commas - like in CSV files? tabs? newlines? What you use to separate the numbers determines how you should parse the file once you've opened it.

On the flip side, out of this whole problem, opening and parsing the input file is probably the most difficult task of this assignment so do the first bit and you are on easy street.

Originally Posted by Swarvy

parsing the input file is probably the most difficult task of this assignment so do the first bit and you are on easy street.

I agree, and even that is pretty trivial compared to many programming tasks.

write some code and post it here if you have any trouble, and we'll try to help.