We have $this->dataStore("data") like this:

name	income
John	$50,000
Marry	$60,000
Peter	$100,000
Donald	$80,000

$count = $this->dataStore("data")->count();
$total_income = $this->dataStore("data")->sum("income");
$average_income = $this->dataStore("data")->avg("income");
$min_income = $this->dataStore("data")->min("income");
$max_income = $this->dataStore("data")->max("income");
$mode_income = $this->dataStore("data")->mode("income");