Thursday, February 28, 2013

Late night study blues. Don't even read.

Good evening all. It's getting late. I've pumped my brain with some caffiene at 9:00 so I know I could stick it out for another couple of hours and still be just fine in class tomorrow without wearing myself out.

I shouldn't be worried about wearing myself out anyway, tomorrow's Friday and there isn't even a finite midterm exam. That's going to be next Thursday. For our last chapter we've been working on very introductory statistics. Note to self: (Note to any of my readers, skip this useless crap)

We're using median, range and mean in a set of values. With these values we can find the Z score and standard deviations from the mean the point is located. There is a formula to get the variance which you take the square root of to get the Standard deviation of a sample. The formula is Sum of X squared (so add together all X values after squaring them)-(Sum of X*Sum of X (or sum of X squared)/n) (number in sample i.e. "10 consecutive nights) ALL divided by n-1. So number in the sample-1. If the values in a set of data is mound-shaped, 68% of values in the data set are between X bar- S (sample mean-1 standard deviation) and x bar+1. 
Empirical rule: Approximately 95% of the values between X bar - 2 S (sample mean and 2 standard deviations from the mean). Virtually all data is between 3 standard deviations of the mean. This has to do with Chebyshev's Theorem. This rule provides a quick way to approximate a standard deviation. Because all data is within 3 standard deviations on either side of the mound shape, or within 3 standard deviations of the mean, the span of the range between the largest and smallest point should be about six standard deviations from the mean. Take the largest value minus the smallest value, but then you must figure out what to divide by. In the last case we would use six because there's 6 standard deviations, but this only works with sample sizes over 200 for some reason. So n >/ 200, Range/6= Range Approximation for S. 50</n</199=Range/5. 16</n</49=Range/4, N</15=Range/sqrRt N. This is to get the value S, which is the sample standard deviation. When you are just given a set of values you can still find the variance which can then be converted to the standard deviation by using the formula Sum x^2 (add together all X values after squaring them)-(Sum of X*Sum of X/n))/n-1 N being the number in the sample given. You can get percentages for probability frequency by dividing the total in the sample that correspond to each value divided by the total number of values (typically given in problem. i.e. 52 sizes of jerseys total and your looking at the set of values for 15 of them selected randomly)

And THAT... is what I've learned over the past few days of studying this stuff. I'm still two days behind. Luckily, because there's no "midterm" tomorrow I've got some time to get caught up. The test tomorrow should just be over what I just described to you, and nothing in later sections that he's gone over the past few days but have me completely lost. I can't skip econ tomorrow like I have the past couple fridays. I've got a quiz tomorrow.

I'm also lucky that the quiz is on chapter 10. Here it is 11:16 and if I get in a solid hour on this, make up some flash cards to take with me in the morning and sneak them in English.. I should be golden. I should also exercise tonight. I feel like I've been so stressed out lately that I've been eating more. Food just tastes good to me lately, and the last time I went grocery shopping I got a sufficient amount of delicious munchies that have me going through my cabinets more frequently.

I'd like to keep this picture for later. I posted it to facebook today as well. Look at that, all the guitar shapes. I intend to own at least one of all of them someday, is that wild? He he he. What guitarist does not fantasize about having an extraordinary collection? 

I also had to revise and write up a works cited page for first English arguement paper. I think it's pretty good. I didn't really utilize the articles as much as I stated my personal opinions on the matter based on common knowledge.. which I hope she won't mark me off for. Really the only thing I used the articles for was for the studies.

I've been working very hard today to have the ability to see Abe tomorrow and be able to relax with him for awhile, as well as go to a bonfire I got invited too. I also intend to practice my guitar, of course. Jake gave me this sick new song tonight. It sounds so cool, guys, it's going to be a challenge. 

This is the song, 

J.S. Bach Invention No. 8 in F Major

 Apparently this is "Neo-classical"

So I've still got this economics to study. I don't want to do it. At 12:30 I'm going to bed whether I feel like it or not cause if I stay up later than that my whole day will be groggy tomorrow.


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