Question

java//
Statistical Analysis of student grades.
1) Create an array of double of size 20
2) Ask user to enter 20 grades
example
Enter 1st student's grade: 85.88 Enter 2nd student's grade: 68.15 Enter 3rd student's grade: 75.45

Answer 1

...
Enter 20th student's grade: 95.20 <enter>
You are free to choose the grades.

3) Print the average and standard deviation of the grades
for example
average: 68.47
stdev: 19.45

4) Assign letter grades to the students.
top %10 will get A (two people in this case)
next %20 will get B (3rd, 4th, 5th, 6th people will get B)
next %40 will get

Answer 2

so what problem do you have?

Answer 3

to write this simple program .

Answer 4

well what have you done till now? have you thought how you should start? I'd say start thinking of a pseudocode.
:)

Answer 5

almost finnish but the sted is not working /public static void main(String[] args) throws Exception {
Scanner in=new Scanner (System.in);
System.out.println("input the number of students");
int arr=in.nextInt(); //if in case Students number less than 20 while (fix==false);{ fix=true; fix=true; boolean fix=false;
double[] grades=new double [arr];
int i;
double sum=0.0;
double v=0.0;
for( i=0;i<grades.length;i++){
System.out.println("input the grade of Student "+i+1);
grades[i]=in.nextDouble();
sum=sum+grades[i];
}
System.out.println("the total is "+sum);
double average=sum/arr;
System.out.println("the Average is "+average);
for ( i=1; i<grades.length;i++){
v =v+(grades[i] - average) * (grades[i] - average);
System .out.print("the grades are "+grades[i]);
}
double std =Math.sqrt((1/arr-1)*v);
System.out.println("the std is "+std);
}
}

Answer 6

could you use a paste site like pastebin.com to paste your code? it is much more readable like that.

Answer 7

sorry that site is forbidden to access here in turkey and I am using the university server so I don't want to trouble with them . I think I've finish it . I found a way to calculate the standard deviation. even though its not the easiest way maybe but still work thank you

Answer 8

oh well if u get more problems message me :) and gj if you made it work!

Answer 9

thanks

Answer 10

@MicroBot
help me I still didn't find a way to print the letters to each student for this conditions
4) Assign letter grades to the students.
top %10 will get A (two people in this case)
next %20 will get B (3rd, 4th, 5th, 6th people will get B)
next %40 will get C (7th, 8th, 9th, 10th, 11th, 12th, 13th, 14th will get C)
next %20 will get D (15th, 16th, 17th, 18th people will get B)
next %10 will get F (19th, 20th people will get B)

5) print the letter grades
1st student's letter grade is A
2nd student's letter is C
3rd student's letter grade B
....

Answer 11

well I dont know what you have done untill now ...but my thoughts are:

* you have 20 students in an array
* you should sort that array from max grade to minimum
*and then see how many students are 10% of 20 students and assign to those x students A grades.
* then see how many are 20% and assign to the next y students in the array , B grade.
* continue to the end...

hope this helps

Answer 12

yeh exactely that's what I have to do but how to order the array "with the students numbers "

Answer 13

try using the sort method of arrays.

http://docs.oracle.com/javase/7/docs/api/java/util/Arrays.html

Answer 14

really I don't understand that would you write the way n codes plz .

Answer 15

Arrays.sort(double[] yourArray);

this will sort yourArray into ascending order though...so you will have to copy your array backwards after the sorting.

Answer 16

btw i am not a java expert so i might even give you a false advice or not the optimal so it would be nice if someone else would confirm or give a look at this :)

Answer 17

well thanks