Computational Organic Chemistry » Assigning a computed NMR ...
Determine the probability of this error using the Student’s t test (with mean, standard deviation, and degrees of freedom as found using their database of over 1700 13C and over 1700 1H chemical shifts). Lastly, the DP4 probability is computed as the product of these probabilities divided by the sum of the product of the probabilities over all possible diastereomers. This process is not particularly difficult and Goodman provides a Java applet to perform the DP4 computation for you! In the paper Smith and Goodman demonstrate that in identifying structures for a broad range of natural [more...]
Date: 2010-09-28 14:36:20
12 Degrees of Freedom: "...trundling around the edges of European ...
"You weren't entitled to the status of refugee, precisely because you were a gypsy. And that's the crux of the problem." Because the Italian authorities decided that nomadism was their natural condition, they made no steps to settle the new migrants in houses like other refugees, but instead created camps for them. The press still calls these campi nomadi, nomad camps. It was a way to sidestep the challenge of integrating the Roma into local communities. The result was ghettoes. And they did what ghettoes always do: they prevented their inmates from developing in step with the rest of [more...]
Date: 2010-10-04 13:04:00
Regression 1: More Properties « Rip's Applied Mathematics Blog
I looked in a statistics book and found that the t-statistic for 9 degrees of freedom and a 95% confidence level was 2.262. (I’m sure I could have gotten Mathematica to tell me that….) I checked it by asking Mathematica for the cumulative probabilites at ± 2.262: What that all means is that the two red points on the following curve mark the boundaries of 95% of the area under the curve. In other words, 2.5% of the area is to the left of the left red dot, and 2.5% of the area is to the right of the right red dot. And that’s what the PValues are telling us: the probability that is really [more...]
Date: 2010-09-27 23:57:06
Excel Master Series Blog: t Tests - How To Use the t Test in Excel ...
The required region of certainty depends upon the degree of certainty required in the test. If 95% certainty is required, then the required region of certainty consists of 95% of the area under the student’s t distribution. The outer 5% is the region of uncertainty. This is also referred to as α (alpha) or the degree of significance. If the t value is large enough to be located all the way out on the x-axis in the 5% region of uncertainty, it can be stated within 95% certainty that the two means are different. A t test can be a one-tailed test or a two-tailed test. A one-tailed test [more...]
Date: 2010-08-03 20:31:00
Chiron: Student, Teacher, Explorer
"I don't know why he's taken me under his wing. He has lots of senior students, but for some reason he's really connected with me. I'm getting things they aren't." Bear with me here. Said in different tones by and about different people, this could be a big red flag... but this was a special case and it got me thinking. Just speculation coming up, a possible way of looking at the world and training. There are students and teachers. That can be a job description or a personality type. Either can be limitless horizons or can lock you in a box. In martial arts, it is far more likely to lock you [more...]
Date: 2010-10-11 14:27:00
Atlantic Hurricanes & the Sun | Watts Up With That?
In my opinion, there are too many degrees of freedom and mechanisms that I would have a difficult time even deducing the sign of the impact. This is a good idear for a idealized climate model where you can turn cranks and switches to even hint at ... We don't know what true effect element “A” has on element “B”, (very low level of scientific understanding etc), but we know for certain (IPCC AR2/3/4/5/6/et al & all the others that haven't been written yet, as we know the [more...]
Date: 2010-10-11 23:09:53
A Monte Carlo Study of Seven Homogeneity of Variance Tests
PASW) uses the Levene Test to test for homogeneity of variance prior to conducting tests of the equality of means in the t-test and One-way ANOVA (Oladejo and. Adetunde, 2009; Zeng et al., 2010; Mazahreh et al.,. 2009). A question arose as to whether the .... the upper critical value of the F-distribution with k–1 and N–k degrees of freedom at a significance level of α. The modified Levene test: The modified Levene test is nearly identical to the original Levene test. The [more...]
Date: 2010-10-08 18:33:55
Makani Airborne Wind Turbine Prototype Test-Flight (Video ...
Date: 2010-10-07 18:59:03