in this video we look at the difference between absolute change and relative change let's begin by taking a look at absolute change we'll start with an example on july 21st 2020 there were 65 277 new covid cases reported on january 8 2021 there were 300 594 new covid cases reported find the absolute change in the number of new daily cases what does it mean when we're asked to calculate the absolute change well the absolute change by definition is simply the absolute value of the ending quantity minus the starting quantity again the absolute value of the ending quantity minus the starting quantity in simple words it's the absolute value of the difference between the two numbers let's apply this to our original problem so on july 21st 2020 there were 65 277 cases this is our starting quantity because it comes first at a later date specifically in january almost six months later we have another amount and that amount is thirty three hundred thousand five hundred ninety four that's our ending quantity to calculate the absolute change in these two quantities we start by taking the absolute value of the ending quantity which is three hundred thousand five hundred ninety-four and subtract from it the starting quantity sixty-five thousand two hundred and seventy seven it's as simple as that that give excuse me that gives us the absolute value of two hundred thirty five thousand three hundred and seventeen now what does the absolute value do to this number an absolute value takes any number and makes it positive since our original number is already positive the absolute value does not affect it so our final answer is simply 235 317 cases this would be the absolute change in the number of new daily cases let's take a look at one more example involving absolute change a politician's approval rating dropped from 52 percent to 47 find the absolute change in the politicians approval rating to calculate that change we again refer to the formula which is the absolute value of the ending quantity minus the starting quantity so we're going to have the ending quantity minus the starting quantity in our specific example our ending quantity happens to be 47 percent because the approval rating is dropping so we're going to start with the ending quantity which is 47 percent and subtract from it the starting quantity which is 52 percent if i take the absolute value of 47 minus 52 i get the absolute value of negative 5 and again the absolute value of any number is simply its positive value so specifically the absolute value of negative five percent is just five percent we would say that the absolute change in the politicians approval rating is five percent i think we're ready now to take a look at relative change relative change is very similar to absolute change except one caveat the relative change takes into account the initial amount you're starting with you're saying how does the change relate to what you started with let's take a look with our examples again on july 21st 2020 recall there were sixty five thousand two hundred and seventy seven new coveted cases and january eighth there were three hundred thousand five hundred ninety four new covid cases this time instead of finding the absolute change we want to find the relative change in the number of new daily cases well to do that we need to look at the formula for relative change the formula for relative change is that relative change is the absolute change divided by the starting quantity again it's the absolute change divided by the starting quantity and recall absolute change is just the absolute value of the ending quantity minus the starting quantity and then we're going to divide by the starting quantity let's apply this formula to our problem we start with our absolute change and if you recall from the previous example we did our absolute change was two hundred and thirty five thousand three hundred and seventeen that was the absolute change in the number of new coveted cases we simply took our end amount minus our start amount and then took the absolute value but now to get the relative change we want to compare that to the starting quantity so we're going to divide by our starting quantity which is 65 hundred and seventy seven now this gives us a fraction and in fact a decimal right fractions are directly related to decimals and more than that it also gives us a percent very often we'll express relative change in terms of percents so let's calculate that now if we take 235 317 and divide it by 65270 we get approximately 3.6048 99122 and that makes sense because two hundred and thirty five thousand is about three and a half times as large as sixty five thousand now the relative change can be thought of as 3.6 but better yet we think of it in terms of a percent so we're going to move our decimal two places to the right and that tells us that our relative change is approximately 360.5 percent in other words you might have heard of like a 360.5 increase we're talking there about a relative change let's look at one more example involving relative change let's take a second look at the politician whose approval rating drops from 52 percent to 47 percent this time we want to calculate the relative change in the politicians approval rating so how do we do that well we start by taking the absolute change and if you recall the difference between 47 and 52 absolute value was 5 so the absolute change was 5 between those two values but to get the relative change we have to divide by our starting value which was 52 we started at 52 percent and then we went down by 5 we're now going to divide these now because we're dividing percents a percent over a percent we can ignore the percent symbol i could go into the math on that but just understand that as long as you're dividing percent on top and on the bottom you can just cancel those out so really all you have to do is plug in on your calculator 5 divided by 52 and 5 divided by 52 is approximately 0.096 again when we think relative change we think in terms of a percentage change so we're going to move our decimal two places to the right and therefore we could say that the relative change in the politician's approval rating was approximately 9.6 in fact it was a drop of 9.6 percent anyways hopefully this video helped to explain the difference between absolute change and relative change if you have any questions at all don't hesitate to email or message me good luck