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Wednesday, August 1, 2018

mother Cow index ~ Quantitative Vs Qualitative analysis


How chill is vanilla ice-cream to strawberry – while one can feel the difference in chillness and measure the degree of cold – there are things which are better measured by feeling and not by scale.  In our school days, it was all about mathematical tables, and the one who could reel off 13 table was a wizard ! ~ do you know what is ‘mother cow index’ ?

Thosedays  life was all about tables ! ~ in Mathematics, a multiplication table is used to define a multiplication operation for an algebraic system.The decimal multiplication table was traditionally taught as an essential part of elementary arithmetic around the world, as it lays the foundation for arithmetic operations with base-ten numbers. It was all about memorising and recalling.

That way, has life turned simple or more complicated – as you would see modern day youngsters struggle for simple multiplications and search for a calci (calculator) or an MS excel sheet.  As someone said, modern day Offices might come to a standstill if Powerpoint and Excel cease to function on a given day !!Excel is a wonderful tool with unimaginable potential. This software is not only capable of doing basic data computations, but one can also perform data analysis using it. Excel, with its wide range of functions, visualization, arrays empowers amazes its users.  In every argument – there are ‘ifs & buts” – in Excel it is scientific.  If(): one of the most useful function in excel. It lets you use conditional formulas which calculate one way when a certain thing is true, and another way when false.

For advanced learners, Statistics is the branch of mathematics dealing with the collection, organization, analysis, interpretation and presentation of data. In applying statistics to, for example, a scientific, industrial, or social problem, it is conventional to begin with a statistical population or a statistical model process to be studied. Populations can be diverse topics such as "all people living in a country" or "every atom composing a crystal". Statistics deals with all aspects of data including the planning of data collection in terms of the design of surveysand experiments.  In every analysis, scales help us measure the physical world. To compare quantities, we  rely on quantitative scales – numerical measurements that tell us something about frequency and quantity. Inches, feet, yards and miles; ounces, quarts, litres and gallons; seconds, minutes, centuries and lightyears are all quantitative scales.

There are qualitative scales too. These are yardsticks that measure observable, but not necessarily numerical, properties – and we use them all the time. Read this interesting article in BBC on this – they  range from chili pepper heat to mineral hardness to ocean breezes to something called the Mother Cow Index. Qualitative scales allow us to label variables with little or no quantitative information. These unusual units of measurement are often colloquial: guesstimations and “as-the-crow-flies” rules of thumb that allow for quick assessments and comparisons.

Qualitative scales prove their usefulness time and again. Without them, we would struggle to conceptualise ideas of pain (a doctor might ask a patient to rank his symptoms) or grade the severity of weather conditions (like the Beaufort Scale does).Date, when measured from an arbitrary epoch such as BC or AD, helps us understand time, while direction measured in degrees from true or magnetic north orients us in physical space.Quantitative scales are much easier to evaluate, since they are effectively comparisons to a known standard. A square-kilometre, a teaspoon of sugar or an hour-long lecture are basically unchanging measurements. Qualitative scales are more subjective. Neither quantitative nor qualitative scales, however, are ever 100% accurate: they are each limited by the uncertainty baked into the definitions of units themselves.Any true measurement, when you get down to it, is arbitrary. Yet the very human urge to appraise, quantify, and compare persists, and so we continuously seek new ways to describe our experience of the world.

In 1805, Rear Admiral Sir Francis Beaufort, an Irish hydrographer in the Royal Navy, wanted a way to more accurately measure ocean breezes. Each day aboard the HMS Woolwich, he recorded in his diary wind force and sea conditions, from eerie calm to violent gales. Today, a “Beaufort 0” means an ocean as smooth as glass, while a "Beaufort 12" indicates crashing waves, hurricane-force wind, whitecaps and greatly reduced visibility.

By and large, qualitative scales fall into one of two categories: Ordinal measurements (in which values can be arranged in a meaningful order), or Interval measurements (in which values can be arranged in a meaningful order, and the difference between two values matters). For example, an earthquake that measures 6.0 on the Richter scale is many orders of magnitude greater than a small trembler of 3.0. So the order of quake size matters, and the interval is also fixed, meaning that Richter’s scale is an Interval scale.  An “extremely satisfied” response on a customer service ranking is not triple the satisfaction of “somewhat dissatisfied”; even the difference between 10C and 20C, while quantitative, is not an intuitive measurement. Some argue that these limitations make qualitative scales inherently less functional.

Indeed, while proper measurement ascribes value to the physical world, our perception of the physical world varies widely. “There are things that we can measure and things we can’t,” says Andrew Hanson, senior research scientist at the National Physical Laboratory (NPL) in the UK. “But even what we canmeasure, we can only do to a degree.”Hanson works in soft metrology: he studies measurements that relate to sensory scales like colour and light, which are quantitative but also subjective. No human can see ultraviolet or infrared light, but even shades on the visible spectrum appear differently from person to person – a difference that has real-world implications.

Think about traffic signals, which must appear red, amber, or green. The way we perceive the brightness of these coloured lights is non-linear: numerical changes in input (watts) don’t always translate to the naked eye, or to human experience.“For a scale to become legitimate, everyone must agree on its units and intervals,” Hanson explains. Despite the fact that they aren’t always linear or mathematical, qualitative scales still seem to get the international greenlight.Take the Scoville scale. Named after its creator, American pharmacist Wilber Scoville, this scale ranks chili pepper spiciness. But the Scoville doesn’t actually measure the amount of spice, or capsaicin, in a pepper; rather, it notes the number of dilutions needed to put out a capsaicin-fuelled fire.At present, qualitative measurements help us translate ideas that are almost poetically incalculable: the length of a city block or the Grand Canyon, the pitch of a teakettle or a lightning strike or a whisper in the dark.

Sounds complicated but true

With regards – S. Sampathkumar
28th July 2018
Inspired by BBC article and largely reproduced from : http://www.bbc.com/future/story/20180726-the-measures-that-dont-need-maths
PS:  For farmers, the literal size of a field was much less important than its utility in sustaining cattle. Ireland once used "a cow's grass" as a unit of measurement — that is, the amount of land needed for one cow. In America, the "mother cow index" determined how many pregnant cows an acre of land could support. As opposed to size, it was a quality measurement.


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