[RESOLVED] New to JavaScript totally stumped

Hi everyone

I am trying to build a JavaScript form using radio buttons and trying to achieve a
watering time calculator using 2 sets of information.
1. 4 different systems
2. 3 different types

All systems + type1 = the variable totals represented below
All systems + type2 = are multiplied by 2
All systems + type 3 = are multiplied by 3.5
If the 'largeplants' check box is selected the total needs to be multiplied by 1.5

The calculateTime function needs to calculate the watering time on click & display an alert box stating the watering time
& The reset button needs to reset the radio buttons.

<!doctype html>
<html>
<meta charset="utf-8">
<title>Perfect Watering Results</title>

<script>

//Calculate Watering Time for Plants
function calculateTime (){
var system1 = 6; //watering time for sand with jetspray
var system2 = 11;//watering time for sand with sprinkler
var system3 = 17;//watering time for sand wih minisprinker
var system4 = 50; //watering time for sand with dripper

var largeplants = * 1.5; //multiply by 1.5 if checkbox is selected

var type1 //watering time for sand with all systems
var type2 = * 2; //watering time for loam with jetspray/sprinkler/minisprinker/dripper
var type3 = * 3.5;//watering time for clay with jetspray/sprinkler/minisprinker/dripper

// Get the number of the selected answer (1, 2, 3 or 4)
for (var i = 1; i <= 4; i++) {

// Get the number of the selected answer (1, 2, or 3)
for (var i = 1; i <= 3; i++) {

}

</script>

<body>
<h1>Home Garden Watering Guide</h1>
<p>Complete the form below to calculate the recommended watering time for your home garden.<br>
<br>
<br>
<form>
<p>Watering System</p>
<label for="jet">Jet Spray</label><br>
<label for="sprink">Sprinkler</label><br>
<label for="mini">Mini Sprinkler</label>
<br>
<label for="drip">Dripper</label>
</p>
</p>
</form>
<form>
<input type="checkbox" id="largeplants" name="plants"
value="largeplants" onClick=" * 1.5 ">
</form>

<form>
<p>Soil Type</p>
<label for="sand">Sand</label><br>
<label for="loam">Loam</label><br>