Question

How would you use confidence intervals in your daily life?

Answer 1

For most things in daily life, you'll never need a formal CI. However, we humans use informal CIs all the time. A formal CI is a mathematical function; an informal CI is a pretty good guess of a range of values.For instance, you may not know how much money is in your pocket down to the penny, but you do know if it's between $100 and $1. That's an informal one, and you'd get pushback from many statisticians about whether it's a CI. also,

A clothin company (say US POLO) makes a jeans of waist sizes 32 and 34. Now, since the jeans is manufactured and made by machines there is a slight margin of error in the waist sizes. Now you and your friend X bought a 32" waist size jeans. You come home and measure the waist size of the jeans individually by the correct way. You find the waist size of your jeans as 31.8" and X's jeans had a waist size of 32.4".

Now, why did the company put a tag of 32" on a 31.8" and a 32.4" jeans? This is because the company assumes that any waist size of jeans within 31.8" and 32.4" is a 32" jeans with a probability of x% where x is usually 95 or 99. This is classified as a 95% or a 99% CI.

  The same process can be undertaken with any kind of data in your life: tire pressure, spending on video games (and video scores), rainfall, time to drive to work or school, prices of grocery items, volume of music heard from next door (in db's), electric bills, prices of gasoline, time spent studying, amounts spent for lunches, times running the 100-meters, time spent with a BFF, and on and on.