150_Missing_Values

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Missing values

Statistically spoken, a missing value is something important. Lot of applications interpret incorrectly missing values as zero.

If among 5 students, you know the result of 4 of them, you should not compute the average as the sum of the 4 known results divided by 5. Unfortunately, lot of applications does.

Similarly, when you raise the temperature each day, if you report the result on a line graph, you should not report a line to zero for the days that you omit to take the mesure.

ChartNew.js take account of missing values and graph will not report missing values as zero. How do you specify a missing value in your data ? When nothing is specified for a value, the value will be considered as a missing value.

Example :

var datamissing = {
labels : ["January","February","March","April","May","June","July"],
datasets : [
	{
		fillColor : ["rgba(220,220,220,0.5)"],
		strokeColor : "rgba(220,220,220,1)",
		pointColor : "rgba(220,220,220,1)",
		pointstrokeColor : "#fff",
		data : [65,59,,81,56,55,],
                    title : "2014"
	},
	{
		fillColor : "rgba(151,187,205,0.5)",
		strokeColor : "rgba(151,187,205,1)",
		pointColor : "rgba(151,187,205,1)",
		pointstrokeColor : "#fff",
		data : [,,40,19,96,27,100],
                    title : "2013"
	}
]
}

Attention : do not specify a missing value as two (double) quotes :’’ and “” are considered as a zero value.

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