There are two broad categories of data in statistics: quantitative data and categorical data. Quantitative data is something you measure or count while categorical data presents data in categories or groups rather than the actual values themselves.
Overview: What is quantitative data?
Quantitative data describe values and numbers which are measured or counted and can be used in basic mathematical functions such as adding, subtracting, multiplying, and dividing. Quantitative data can be stratified into discrete and continuous data.
Quantitative data is the value you get when you measure something with a measuring device such as a tape measure, watch or scale. One of the characteristics of quantitative data is that it can take on any value over a range of possible values and can be infinitely subdivided as a function of the resolution of your measuring device.
Alternatively, discrete data is counted, not measured. You can count 15 defective parts, 12 late deliveries, or 100 accident fatalities. It is irrelevant to talk in terms of 15.3 defective parts or 101.435 accident fatalities. In both cases, continuous and discrete data can be used in mathematical operations.
An industry example of a quantitative data
Incoming inspection wanted to capture data on its accept/reject rate for bags of powder raw material. One person wanted to just collect data on whether the bag was accepted or not. The company Black Belt (BB) wanted to collect the exact weight of the bags since they were paid for by weight. The BB was hoping to spot trends of over/under weight bags.
The company Master Black Belt (MBB) agreed so incoming inspection started to weigh sample bags to collect data on the exact weight of bags. This type of data was continuous versus the previous discrete accept/reject data.
Frequently Asked Questions (FAQ) about quantitative data
What is the difference between continuous and discrete data?
Continuous data is collected by measuring something while discrete data is collected by counting things.
What determines how small continuous data can be subdivided?
It will be a function of the resolution of your measuring device. A ruler with only inch marks is not capable of measuring ½, ¼, ⅛, or any increment less than an inch.
Which type of data is preferred, continuous or discrete?
Continuous data is preferred because it can provide greater granularity.