/* Compute chi-squared test for me please */

#include <stdio.h>

#define MAX_BINS 100

int main()
  {
    int i, bins;
    int expected[MAX_BINS];
    int observed[MAX_BINS];
    float sum = 0.0;

   printf("How many bins? ");
   scanf("%d", &bins);
   if( bins > MAX_BINS )
     {
       fprintf(stderr, "Sorry, but I can't do that many!\n");
       return;
     }
   printf("Enter expected value for each bin: ");
   for( i = 0; i < bins; i++ )
     {
       scanf("%d", &expected[i]);
     }
   printf("Enter observed value for each bin: ");
   for( i = 0; i < bins; i++ )
     {
       scanf("%d", &observed[i]);
     }

   /* compute chi-squared statistic */
   sum = 0.0;
   for( i = 0; i < bins; i++ )
     {
       sum += (observed[i] - expected[i]) * (observed[i] - expected[i]) / expected[i];
     }

   printf("Sum: %f \n", sum );
   printf("Degrees of Freedom: %d\n", bins-1 );
}