00:01
With the information that the correlation coefficient is equal to negative 0 .918 between violent crime rates and the percentage of the population with a cell phone, we'd like to know will the crime rate decrease if more people have cell phones? so that is, if this percentage of the population with cell phones were to increase, can we expect that the crime rate will decrease? and looking at this correlation coefficient, what we see immediately is that it is very highly negative.
00:26
So this is a pretty strong negative correlation between these two variables, meaning that as one increases, the other tends to decrease.
00:35
But that's not necessarily implying to us anything about causation.
00:40
We're just seeing that they tend to move together.
00:43
So given this information of just this linear correlation coefficient, we can't actually say whether or not that crime rate would decrease if more people have cell phones.
00:52
There's no definitive causality between those two variables.
00:57
And this is where this idea of lurking variables comes into play.
01:01
That's some variable which is impacting both violent crime rates and that percent of the population with a cell phone.
01:08
So what could exist within this study that would be impacting both of these to maybe suggest that they have such strong correlation, but really something else is at play.
01:18
And this could be something like political stability...