average questions

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  <h1>Please look in the code below for 4 JavaScript practice problems.</h1>
  <p>(These problems don't include any SVG manipulation, so you will need to open the developer console in order to see the output of your code)</p>
  <script>

states = [{name: "Alaska", id: "AK", population: 741894},
            {name: "Virginia", id: "VA", population: 8411808},
    				{name: "Arizona", id: "AZ", population: 6931071},
            {name: "Florida", id: "FL", population: 20984400}]
            
  // Problem 1: using d3.mean(), compute and print the average (mean) 
  // population of the states in the states array
 
 var avg = d3.mean(states, function(d) {
 return d.population; });
 console.log(avg)
  
  
  // Problem 2: WITHOUT using d3.mean(), compute and print the average (mean) 
  // population of the states in the states array
//creating a loop, defining i and giving it an itial value of 0, go through as long as i is less than states.length is less than 0 (there are 4 for length of states), we will add 1 to the value of 1 (i++) as long as this statement is true  
 //states[0] gives first, states[1] returns second, and so on... and states [i] goes through the loop we created, average += keeps adding averages of each population
 console.log("without using d3.mean")
var average = 0; 
    
for (i=0; i < states.length; i++){
  average += states[i].population; 
}
      average = average / states.length;
 console.log(average)   
 
 
console.log('another way of doing it') 
 
 var populations = 0;
 var numberofstates = 0;
    states.forEach(function(d){
      populations += d.population;
      numberofstates++;
    })
    var mean = populations/numberofstates;
    console.log(mean)//each time we go through the array, it knows we went through it another time
      
console.log('using a while loop');
    
    
    
  </script>
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https://d3js.org/d3.v4.min.js