Question

In this lab we will write 3 functions:

GenData: This function will take an integer parameter and return a vector with that many random integers generated in the range of 0 and 100 (rand()%101). Seed the random number generator with 22.

Mean(): This function will take a vector and return the mean.
Variance(): This function will take a vector and return the population variance, as: [Sum for values[( x_i - Mean )^2]] / (number of items)

In Main:

• Use GenData to generate a vector with 100 random values.
• Use Mean() to calculate the mean of the vector, and print formatted with 2 decimal points as below:
  • "Mean=25.11"
• Use Variance() to calculate the variance of the vector, and print formatted with 2 decimal points as below:
  • "Variance=25.11"

Example Output:
83, 89, 54, 38, 2, 84, 47, 88, 78, 55,
Mean=51.62
Variance=905.08

Given:

#include <iostream>
#include <vector>
#include <cstdlib>
#include <iomanip>
#include <cmath>
using namespace std;

vector<int> GenData(int n){
//should generate n random values and return them.
}

double Mean(vector<int> d){
unsigned int i;

//return mean of all values in vector.
}
/*Variance function
sum +=(your current X value - mean)^2
return variance - > [ sum/total size of vector]
*/

int main(){
int i;
vector<int> d;
d = GenData(100);

for (/*loop for 10 values*/){
cout << d.at(i) << ", " ;
}
return 0;
}
in c++ pls

Answer 1

Code:

#include <iostream>
#include <vector>
#include <cstdlib>
#include <iomanip>
#include <cmath>
using namespace std;

vector<int> GenData(int n) {
        //should generate n random values and return them.
        srand(22); // set seed to 22
        vector <int> v; 
        // generate n numbers
        for(int i=0;i<n;i++){
                int x = rand()%101;
                v.push_back(x);
        }
        return v;
}

double Mean(vector<int> d) {
        int n = d.size(); // no. of elements in vector
        unsigned int i = 0; // use to store sum
        for(int j=0;j<n;j++){
                i+= d[j]; // add values to sum
        }
        // mean = sum of all no. / size
        double mean = i/(n*1.0);
        //return mean of all values in vector.
        return mean;
}

/*Variance function
sum +=(your current X value - mean)^2
return variance - > [ sum/total size of vector]
*/
double Variance(vector <int> d){
        double mean = Mean(d); // find out mean
        double sum = 0;
        int n = d.size(); // no. of elements
        for(int i=0;i<n;i++){
                sum += (d[i]-mean)*(d[i]-mean); // add ( x_i - Mean )^2
        }
        // divide by no. of items to find variance
        double var = sum/n;
        return var;
}


int main() {
        int i;
        vector<int> d;
        d = GenData(100);

        for (int i=0;i<10;i++) {
                cout << d.at(i) << ", " ;
        }
        cout<<endl;
        double mean = Mean(d);
        double var = Variance(d);
        cout<<"Mean="<<mean<<endl;
        cout<<"Variance="<<var<<endl;
        return 0;
}

Code Screenshot:

Code output:

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Code along with screenshots and comment has been added.

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