What the hell is a standard deviation?

I suppose it's a good idea to tell you a little bit about us and explain our rating system. Both are pretty dorky, but that's okay. Consider it part of our charm.


About us... We moved to Charlotte this past August from Chapel Hill (GO HEELS!). We like to eat and we're pretty sure we know what good food is. We're not saying we know what everyone will like, but we definitely know what we like. She's a scientist and he's a psychologist. We like to know how things work and what makes them delicious and there's a fair amount of experimental cooking done at our house. Thank goodness for friends willing to be guinea pigs. We also have a fair bit of wine/beer snobbery but we aren't obnoxious about it, promise. 


Now about this rating system... Remember way back in some math or science class in college when you saw something like this? 

Ack! Too many Greek letters! But, that's not important. It's just the math behind a standard deviation curve. What's important is how this applies to our rating system. Check out this graph: 

Ack! That's no better! Well, here goes with my attempt to explain... We rate things from -3 to 3 sigmas (aka standard deviations). This covers essentially all restaurants in our vast experience (99.8% is almost 100%, just go with it), from the very worst to the very best. If we rate something a zero, it's perfectly average: 50% are better, 50% are worse. Not bad, not good, just average. If we rate something a +1 it's better than 84.1% of places; if it's a +2 it's better than 97.7%; if it's a +3 it's better than 99.8%. So, you can see there won't be very many +2s or +3s. And hopefully, not many negatives either. I imagine if we ever gave a place anything worse than a -2, there would be a corresponding call to the health department and quite possibly a trip to the ER. 


So, does all that make sense? Yes? Excellent.