**Year to Year and Averages**

As you can see from the graph above, the past two years have been a little above average. Although we have not had a record breaking this year, although we did have one last year.

Last year it rained 37 out of the 127 days, meaning we had rain 29% of the time (days speaking) last year.

This year it rained 51 out of the 127 days, meaning we had rain 40% of the time (days speaking) this year.

Rain is rain or snow.

**Is Weather Data Normal?**

Weather needs to be normal for a lot of the analysis we use. If we want to assume that a day was record hi, or that

*global warming*is increasing the temperature, then we need the data to be normal.

As you can see, the weather data for Jan 5 are normal. With a [nerd alert] Shapiro Wilkins p-value of .19, we can say the data are normally distributed.

What this allows us to do, is to see if we have had any statistically significant days since 1936. We actually have!

High Points

1950 62 Degrees

1997 60 Degrees

2009 58 Degrees

Low Points

1968 18 Degrees

1958 18 Degrees

**Is the Earth Getting Warmer?**

Always a debatable topic, and I'm not going to side really on it. I'll just throw some data at you.

2011 out of 127 days 110 of them were above average on temperature

2010 out of 127 days 100 of them were above average on temperature

However, as we can see above, the two different years do not look that different. The p-value is a sad .486. So we can conclude that there is not a statistical difference from the temperatures before.

Now if we subset pre 1997 and post 1997, we get something a little more likely to differ. Here is the thing though, that P-value is not statistically significant either, its p-value is .188 . So we conclude that the temperatures in Washington DC have remained Normally around their average since 1936, and that extreme temperatures were not common.

Here is what Jan 5th has looked like since 1936

## 1 comment:

Very nice post Patchus. A lot of your terminology (except the really big words) makes sense to me now that I have taken Bus. and Econ Statistics I.

Oh just so you know, the word verification I have to enter to post this comment is "skete."

Skete Skete to you my friend.

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