stream of many 11's:

while (row = this.read()) {
	crunchdata.avg 
		= +(( crunchdata.avg
		+ row.temperature ) /2).toFixed(4)
		;
}

= 11


while (row = this.read()) {
	crunchdata.avg 
		= ( crunchdata.avg
		+ row.temperature ) /2)
		;
}

= 10.9999999