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C language to calculate mean,variance


 
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# 1  
Old 01-08-2008
Java C language to calculate mean,variance

Here I want to calculate mean,variance and sum from a file
1.1*2*4*22*211*22*12*22*22*11
2.2*2*22*12*22*11*11*122*33*22
3.9*7*22*88*87*98*67*66*56*66*11
As this is a large file and i am trying to write in c

where formulae of

MEAN = 1/N (X1...+..Xn)
Variance = square root of 1/N-1 (X1+.,,Xn - mean)2

So simply question say in this example we have one file where first part want to calculate mean and variance
again second part calculate mean and variance ..respectively and save the result

#include <math.h>
void moment(float data[], int n, float *ave, float *var)

{
void nrerror(char error_text[]);
int j;
float ep=0.0,s,p;
if (n <= 1) nrerror("n must be at least 2 in moment");

s=0.0;
for (j=1;j<=n;j++) s += data[j];
*ave=s/n;

what will be the code for variance?
Can rewrite the program with mentioning of open file and closing of file
Thanks
# 2  
Old 01-08-2008
Code:
#include <math.h>
void moment(float data[], int n, float *ave, float *var)

{
    void nrerror(char error_text[]);
    int j;
    float ep=0.0,s,p;
    if (n <= 1) nrerror("n must be at least 2 in moment");
                                              
    s=0.0;
    for (j=1;j<=n;j++) s += data[j];
      *ave=s/n;
    variance = sqrt(pow((s - avg), 2)/(n - 1));

# 3  
Old 01-08-2008
Is this a homework assignment?? I keep reading posts with really "interesting" program requirements that seem to only have a theoretical benefit.
# 4  
Old 01-08-2008
Quote:
Originally Posted by frank_rizzo
Is this a homework assignment?? I keep reading posts with really "interesting" program requirements that seem to only have a theoretical benefit.
ask the source code for variance that i have got..
home work assignment only if u don't attempt on a problem and writing questions only....
sorry if bother
# 5  
Old 01-09-2008
Question

Quote:
Here I want to calculate mean,variance and sum from a file
1.1*2*4*22*211*22*12*22*22*11
2.2*2*22*12*22*11*11*122*33*22
3.9*7*22*88*87*98*67*66*56*66*11
As this is a large file and i am trying to write in c
Are you trying to find the mean & variance of all the data points in the file or for every line of the file?

Smilie
# 6  
Old 01-09-2008
Quote:
Originally Posted by shamrock
Are you trying to find the mean & variance of all the data points in the file or for every line of the file?

Smilie

Dear Shamrock,
Here trying to derive mean and variance for every line of the file Hereby each line is just say as separate entity.
That is In one file Input is
1.1*2*4*22*211*22*12*22*22*11 then derive its mean and variance
2.2*2*22*12*22*11*11*122*33*22 same derivations......
continue............etc.etc....
# 7  
Old 01-09-2008
Question

Quote:
Originally Posted by cdfd123
Dear Shamrock,
Here trying to derive mean and variance for every line of the file Hereby each line is just say as separate entity.
That is In one file Input is
1.1*2*4*22*211*22*12*22*22*11 then derive its mean and variance
2.2*2*22*12*22*11*11*122*33*22 same derivations......
continue............etc.etc....
So let me see if I understand your post. You need the mean & variance for every line of input and every one of those input lines has ten data values separated by the asterisk character and the first data value is a floating point number like 1.1 2.2 yada yada...correct me if I am wrong.
The code you have posted does not seem to be able to compute the mean and variance of every line of input.

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