search for: significant

...unmap() has very little performance impact in > either direction, so that's good: > > ### 2to3 ### > 35.590589 -> 35.824554: 1.0066x slower > > ### bzr_startup ### > Min: 0.157976 -> 0.155976: 1.0128x faster > Avg: 0.167575 -> 0.168924: 1.0081x slower > Not significant > Stddev: 0.00334 -> 0.00716: 2.1463x larger > Timeline: http://tinyurl.com/39thymp > > ### call_method ### > Min: 0.878663 -> 0.884666: 1.0068x slower > Avg: 0.887148 -> 0.888667: 1.0017x slower > Not significant > Stddev: 0.02062 -> 0.02074: 1.0058x larger &gt...

...ran the speed tests. It seems using mmap()/munmap() has very little performance impact in either direction, so that's good: ### 2to3 ### 35.590589 -> 35.824554: 1.0066x slower ### bzr_startup ### Min: 0.157976 -> 0.155976: 1.0128x faster Avg: 0.167575 -> 0.168924: 1.0081x slower Not significant Stddev: 0.00334 -> 0.00716: 2.1463x larger Timeline: http://tinyurl.com/39thymp ### call_method ### Min: 0.878663 -> 0.884666: 1.0068x slower Avg: 0.887148 -> 0.888667: 1.0017x slower Not significant Stddev: 0.02062 -> 0.02074: 1.0058x larger Timeline: http://tinyurl.com/2fm39l2 ### c...

Hi, I have been unable to find how to go about changing the significance level in R for hypothesis testing and regression analysis. R has a default setting to alpha=95% (a significance level of 95%), but I want to be able to decrease or increase this level when necessary. If you could give me instructions on how to change the significance level in R for hypothesis testing and regression analysis

This has a stats question and a R question. I am sure there are many core statisticians here how would know the answer to this simple question. In determining the significant comparisons using the methods in multcomp, the ones that are designated as significant are the ones that do not intersect the zero line. What is the physical meaning of this and why are those considered significant? I can sort those out and pick out by their adjusted pvalues to pick the top ones co...

Hi all! Writing a paper using a lot of boxplots I was asked to mark the significant differences between plotted groups using "stars on top". These stars are found freqeuntly in medical papers and printed above boxplots when there is a significant difference (usually using a bar to indicate which groups are meant if there are more then two in a plot). I was able to ca...

Hi, I have a question to ask. if in a linear regression model, the independent variables are not statistically significant, is it necessary to test these variables in a non-linear model? Since most of non-linear form of a variable can be represented to a linear combination using Taylor's theorem, so I wonder whether the non-linear form is also not statistically significant in such a situation. Best Regards Hsi...

...ed Statistics with S-Plus" 3rd ed., footnote on page 153 regarding a model lm(Gas~Insul/(Temp+I(Temp^2))-1,whiteside), I read "Notice that when the quadratic terms are present, first degree coefficients mean 'the slope of the curve at temperature zero', so a non-significant value does not mean that the linear term is not needed. Removing the non-significant linear term for the 'after' group, for example, would be unjustified." AFAIK, t-test for significance of a coefficient is not based on the assumption that the variables of the linear mod...

Hi, let's say I have a simple ANOVA model with 2 factors A (level A1 and A2) and B (level B1 and B2) and their interaction: aov(y~A*B, data=dat) It turns out that the interaction term is not significant (e.g. P value = 0.2), but if I used glht() to compare A1 vs. A2 within each level of B, I found that the comparison is not significant when B=B1, but is very significant (P<0.01) when B=B2. My question is whether it's legal to do this post-hoc comparison when the interaction is NOT sign...

Hi, I am just a little confused of mian effect in the analysis of variance (ANOVA) when you include or do not include an interaction term. Let's assume a simple case of 2-way ANOVA with 2 factors A and B, each with 2 levels. If it shows that main effect for A is significant when the interaction between A and B is NOT included, and the main effect for A is NOT significant when the interaction is included, what simply does this difference mean? I understand that main effect for A generally means averaging over levels of B, is this explanation for the situation when inte...

I have 11 possible predictor variables and use them to model quite a few target variables. In search for a consistent manner and possibly non-manual manner to identify the significant predictor vars out of the eleven I thought the option "select=T" might do. Example: (here only 4 pedictors) first is vanilla with "select=F" > fit1<-gam(target~s(mgs)+s(gsd)+s(mud)+s(ssCmax),family=quasi(link=log),data=wspe1,select=F) > summary(fit1) Family: quasi...

Hi, How to represent a rounded number ending with 0 with 2-significant digits? If I have for ex, 0.8031 and I use signif or round with digits = 2, I'll get 0.8. If I use format, I get character type (even if I pass number as parameter) and if I convert with as.numeric, I'll lose one significant digit (0): > format(13.7, nsmall = 2) [1] "13.70" &...

Hi everyone, I can't figure out how to format numbers to have a certain number of significant figures (as opposed to decimal places) without using scientific notation and including trailing zeros if necessary. e.g. I would like to achieve the following: 0.800001 ---> 0.8000 123.4567 ---> 123.4 0.1234567 ---> 0.1234 7.654321 ---> 7.654 7654321 --->...

Hi.. I'm using gam() to fit a spline model for a data set that has two predictor variables (say A and B). The results indicate that the higher order interaction terms are significant. The R^2 jumps from .5 to .9 when I change the maximum order for the interaction from 10 to 15 (i.e. (AB)^10 to (AB)^15). Is there any way of finding out which of the terms in the model are really "significant" so that I could drop some of the terms from the model? Thanks, nirmal

Hi all I am not a C programmer, but I am trying to understand formatC to get consistent printing of reals to a given number of significant digits. Can someone please explain this to me? These first three give what I expect on reading ?formatC: > formatC(0.0059999, digits=2,format="fg",flag="#") [1] "0.0060" > formatC(0.59999, digits=2,format="fg",flag="#") [1] "0.60&qu...

HI Dave, My comment was based? on: " >The main question with this test was if the interaction term is significant (i.e. growth rate). However, my question is could I also look at the p-values of the main effects to ?>say if body mass increase significant with body mass?" Here, the result shown were from the summary of the linear model.?? We report the p-values of the main effects and intenraction from...

Hello, I am using the gpls package for modelling vegetation classes. My problem is that I now want to know which input variables are significant for the modelling of the classes to recalculate the equation again with just the selected variables. I think I can analyse the significance of the variables via their weights. I used the "gpls1a" term for two group classification. Here my code: ------------------------------------------...

Is there a function in R that could find the significant digit of a specific number? Such as for 3.1415, return '5'? Thanks in advance. [[alternative HTML version deleted]]

Hello R-help I don’t know how to interpret significance from the contr.poly() function . From the example below : how can I tell if data has a significant Linear/quadratic/cubic trend? > contr.poly(4, c(1,2,4,8))               .L         .Q          .C [1,] -0.51287764  0.5296271 -0.45436947 [2,] -0.32637668 -0.1059254  0.79514657 [3,]  0.04662524 -0.7679594 -0.39757328 [4,]  0.79262909  0.3442576  0.05679618 > > diff(contr.poly(4, c(1,2,4,...

dear list, i am running a within-design ANOVA with 4 factors (4,4,2 and 2 levels each). the last one is a time factor comprising two different treatment timepoints. i fit a mixed-effects model using lme and apply the anova function to the outcome. according to this analysis, there are highly significant main effect on the first and the time factor. i then checked the boxplots for the two 4-level factors for each timepoint separately: there is a difference or barely 1 to 2 units; actually, the plots look pretty much alike. also, there is no notable interaction effect. i am really wondering how this...

...have the eyesight power of both left and right eyes for each participant (e.g. 0.75, 0.5). Each participant then had to throw basketballs into a hoop and the number of successful throws was recorded. I would like to do two things: 1. Test whether the eyesight power of the left and right eyes are significantly different from each other. 2. Test whether the number of successful throws is significantly affected by eyesight power (i.e. is there a difference between those people who have similar powers in left and right eyesight, to those who have significantly different powers?) I know that I may not ha...