tag:blogger.com,1999:blog-8909074830238091680.comments2015-04-20T23:49:06.913+10:00Jeromy Anglim's Blog: Psychology and StatisticsJeromy Anglimnoreply@blogger.comBlogger790125tag:blogger.com,1999:blog-8909074830238091680.post-87293188079464334032015-04-03T17:19:59.543+11:002015-04-03T17:19:59.543+11:00I have an R package that uses bootstrapping to com...I have an R package that uses bootstrapping to compare r-squared when the sample is the same.<br />https://github.com/jeromyanglim/personalityfacets<br /><br />Anglim, J., & Grant, S. L. (2014). Incremental criterion prediction of personality facets over factors: Obtaining unbiased estimates and confidence intervals. Journal of Research in Personality, 53, 148-157.<br />https://scholar.google.com.au/citations?view_op=view_citation&hl=en&user=mF0H9gUAAAAJ&citation_for_view=mF0H9gUAAAAJ:0aBXIfxlw9sCJeromy Anglimhttp://www.blogger.com/profile/12949204812496382042noreply@blogger.comtag:blogger.com,1999:blog-8909074830238091680.post-1041704933353895572015-04-03T17:16:30.755+11:002015-04-03T17:16:30.755+11:00You could (a) convert the sum of z-scores to a z-s...You could (a) convert the sum of z-scores to a z-score; and then (b) take the cumulative distribution of the standard normal; and (c) multiply this by 100.<br /><br />For example, in R say you have a variable zraw<br /><br />zraw <- c(-0.2, -0.3, 0.9, 1)<br /><br />Then <br /><br />pnorm(scale(zraw)) * 100<br /><br />will give you a variable scaled to lie between 0 and 100.Jeromy Anglimhttp://www.blogger.com/profile/12949204812496382042noreply@blogger.comtag:blogger.com,1999:blog-8909074830238091680.post-70896971187434067192015-03-20T05:05:23.698+11:002015-03-20T05:05:23.698+11:00There are a couple of online tools now. This one i...There are a couple of online tools now. This one is fairly simple to use:<br />http://www.bruot.org/ris2bib/Anthonyhttp://www.blogger.com/profile/00238010136023190099noreply@blogger.comtag:blogger.com,1999:blog-8909074830238091680.post-17085943481830897962015-02-05T06:24:51.062+11:002015-02-05T06:24:51.062+11:00I have multiple variables that I have converted in...I have multiple variables that I have converted into z scores, but I want to make the final scale a 0-100 scale, as most people can't interpret z scores. Does anyone know how to take multiple summed z scores and transform them into a 0-100 scale? <br /><br />Thanks! Spence Purnellhttp://www.blogger.com/profile/14382935805638173913noreply@blogger.comtag:blogger.com,1999:blog-8909074830238091680.post-17895838047493200562015-01-27T02:26:17.689+11:002015-01-27T02:26:17.689+11:00hi i would really appreciate if you can help me ou...hi i would really appreciate if you can help me out with this question:<br />http://math.stackexchange.com/questions/1119357/help-with-sample-size-calculation<br />i got an answer which i think is inaccurate<br />thanks so much!yohanan hasandlarhttp://www.blogger.com/profile/00897804323848742962noreply@blogger.comtag:blogger.com,1999:blog-8909074830238091680.post-84807253606162674302015-01-06T22:47:56.600+11:002015-01-06T22:47:56.600+11:00is it a good impression that an Imai et al.'s ...is it a good impression that an Imai et al.'s approach to mediation analysis ('mediation' package) is something different than Baron and Kenny's approach? Lili JKhttp://www.blogger.com/profile/10883577776823925707noreply@blogger.comtag:blogger.com,1999:blog-8909074830238091680.post-7104692587843168122014-11-13T04:05:13.994+11:002014-11-13T04:05:13.994+11:00How can this be adapted to compare coefficients of...How can this be adapted to compare coefficients of determination?Rizwan Malikhttp://www.blogger.com/profile/11686617730809982233noreply@blogger.comtag:blogger.com,1999:blog-8909074830238091680.post-65083039596809526792014-10-20T06:00:00.662+11:002014-10-20T06:00:00.662+11:00Hi. I am so happy you wrote this article. I have b...Hi. I am so happy you wrote this article. I have been voraciously looking for some information regarding this. <br />I did a Master degree in organisational psychology via correspondence (without a graduate degree in it. I graduated as an engineer.). Would that have any value in Australia? I do not have any experience in this field.:(<br />Everywhere I read, I read about a requirement of 6 year course. <br />Can you throw some light on that.confused psychhttp://scribblography.wordpress.com/noreply@blogger.comtag:blogger.com,1999:blog-8909074830238091680.post-7903379996748447392014-09-18T13:01:22.329+10:002014-09-18T13:01:22.329+10:00Hi Christopher,
If you are using an established ...Hi Christopher, <br /><br />If you are using an established psychological scale like the IPIP, then you would generally just score the test as the test designers intended it to be scored. <br />This allows your results to be easily comparable to other studies that have used the same scale. <br />In such cases the exploratory factor analysis is generally just a guide to check that such an approach is reasonable.<br /><br />However, if you've modified the items a lot, then yes, you would need to perform exploratory factor analysis. In general, creating a scale is a big job, and I would advise against modifying personality tests. <br /><br />That said, you have adapted the test and perhaps you have good reasons for doing it.<br />In terms of resources, check out:<br /><br />The EFA lecture and tutorial as part of this course:<br />http://jeromyanglim.blogspot.com.au/2013/10/tutorials-answers-and-data-files-for.html<br /><br />And here are some general readings of EFA:<br />http://jeromyanglim.blogspot.com.au/2009/10/exploratory-factor-analysis-and-scale.html<br /><br /><br /><br /><br /><br /><br /><br /><br />Jeromy Anglimhttp://www.blogger.com/profile/12949204812496382042noreply@blogger.comtag:blogger.com,1999:blog-8909074830238091680.post-59502233469487780152014-09-16T04:05:00.632+10:002014-09-16T04:05:00.632+10:00Hello Jeromy!
Thanks for providing an interesting...Hello Jeromy!<br /><br />Thanks for providing an interesting blog! I’d appreciate it greatly if you could give me some advice or direct me to relevant resources concerning scale development.<br />Being a bit over ambitious 3 year student (psychology) I was/am interested to research the relationship between personality in first year students and their future academic performance (i.e. study pace, GPA, drop-out and motivation). I was afraid social desirability would influence the responses, as it was administered during their admissions to my university. Thus, I created my own item pool, inspired from IPIP scales. The questionnaire contains 160 items and is answered with a 6-point likert-scale.<br />I have now finished gathering my sample, resulting with approx. 500 respondents. The next procedure for me, which I sadly understand too little about, is to perform dimension reduction (I use SPSS):<br /><br />a) Decide which factor solution and rotation would be appropriate<br />b) Remove items with low factor loadings. Back to Step a.<br />c) Decide on the numbers of factors to extract<br />d) Convert raw scores into to new scores based on their factor loadings appropriate for further regression analyses to my dependent variables.<br /><br />1. Do you have any ideas or advice, which factor-solution & rotation would be appropriate for each step? <br />2. Which method would you recommend to compute factor scores? <br /><br />Greetings from Finland,<br />Christopher<br />Christopher Harjuhttp://www.blogger.com/profile/07596527347384472949noreply@blogger.comtag:blogger.com,1999:blog-8909074830238091680.post-79018844895836833512014-08-15T19:57:28.721+10:002014-08-15T19:57:28.721+10:00Hi Jeremy and fellow readers. Thank you Jeremy for...Hi Jeremy and fellow readers. Thank you Jeremy for your interesting and informative post. I really appreciate the content on your blog and appreciate the effort you put into making it available.<br /><br />Similar to Michael Reinhard, I work at a small private institution where I cannot justify the licensing fees for SPSS. I also teach statistics and research methods to undergraduate students and made the switch to R about 4/5 years ago. Here in South Africa, the history of Apartheid and an educational system struggling to come to grips with its own socio-political context, means that students come in to study with frustratingly low levels of mathematical and computer literacy. Getting math-phobic students to grasp statistical concepts is difficult enough, making them sit in front of a console and type in commands is just too intimidating for most (as suggested by jrkrideau). For this reason I teach them using the Rcmdr package. It has all the statistical functions that I need, the students get to see the commands that are run, and I can get them to play around with functions and arguments in the script window to gradually ease them into programming their own scripts. The advantage of this approach is that it provides an easy middle ground between the SPSS mental model and the R approach. Rcmdr makes it possible for students to see and edit their data in a tabular format, they can choose operations using an intuitive and helpful (it often prevents irrational analytical options from being chosen) menu interface, and yet they can still load additional packages, and run additional functions to add to the default outputs. In terms of teaching materials, in the past I have used Howell's text and provided the students with a DVD that has a number of tutorials that goes through the analysis in R we cover and interpretation of output using examples. This is the downfall in using GUIs, it is not easy to incorporate their usage in texts without taking up a lot of space, but the DVD approach is useful. I have ordered Field's text but haven't had a chance to read it yet, and I just downloaded Navarro's book and will have a look at that when I get a chance. I would definitely like to transition to an R based text some time in the future. I prefer to teach my students in R because it is affordable to them and creates opportunities for those that really want to grow their knowledge and skills (it provides them with an asset they can continue using after they leave the class and a propriety licence would have expired). Also, as this post suggests (but you focus more on stats than research) it allows for transference of learning between subjects. For example, in my psychometrics class I refer them to functions for DIF or other concepts they are learning to play around with at home with using R. By giving them an opportunity to play with these functions they improve their understanding of concepts and retention of new material. <br />The biggest challenge and disadvantage of using R as a teaching medium is articulation options for students. Where I teach (WC province in SA) students entering any one of the big state universities for post-grad will have to transition to SPSS for their post-graduate work, they will not have the opportunity to develop their 1st level statistical skills (e.g.: linear models and basic descriptives) or learn 2nd level statistical approaches (e.g.: modelling approaches such as PLS, SEM, and CFA or other multivariate techniques). Only those that are very motivated and competent, will be able to go on make use of stackoverflow, youtube videos, or workshops to develop this kind of competence.<br /><br />Kind Regards,<br />ConradC.S.Zygmonthttp://www.blogger.com/profile/09735050366969025470noreply@blogger.comtag:blogger.com,1999:blog-8909074830238091680.post-38870730180559214342014-08-10T00:01:33.738+10:002014-08-10T00:01:33.738+10:00The best latex APA is actually using biblatex, not...The best latex APA is actually using biblatex, not bibtex. biblatex uses your .bib file & also lets you use natbib citation styles.Joannahttp://www.blogger.com/profile/02968914847649268737noreply@blogger.comtag:blogger.com,1999:blog-8909074830238091680.post-65520863681001977102014-08-08T17:00:35.541+10:002014-08-08T17:00:35.541+10:00Better avoid table and use div..more ...Positionin...Better avoid table and use div..more ...<a href="http://www.corelangs.com/css/box/divindiv.html" rel="nofollow">Positioning Div</a><br /><br />linglingmaakihttp://www.blogger.com/profile/09477565569807599471noreply@blogger.comtag:blogger.com,1999:blog-8909074830238091680.post-24457663224213667662014-07-08T20:29:12.836+10:002014-07-08T20:29:12.836+10:00Hi Jeromy,
I have a data set containing 30 Binar...Hi Jeromy,<br /><br />I have a data set containing 30 Binary Variables (1,0) . I would like to perform SEM on these 30 Binary Variables against 4 Dependent Variables. Can you please explain the step by step procedure in R to perform the SEM analysis (R Code)Avinshhttp://www.blogger.com/profile/14272266272192325792noreply@blogger.comtag:blogger.com,1999:blog-8909074830238091680.post-11588539162649585572014-05-29T23:53:03.814+10:002014-05-29T23:53:03.814+10:00I am the first timer for using apacite, and got th...I am the first timer for using apacite, and got the following error message:<br /><br />!undefined control sequence. <br />1.1216 \st@rtbibchapter<br /><br />What's this? Thanks. Lihui Baihttp://www.blogger.com/profile/10038624117089266350noreply@blogger.comtag:blogger.com,1999:blog-8909074830238091680.post-50547165731347114682014-05-23T16:29:21.122+10:002014-05-23T16:29:21.122+10:00A great new course for beginners on youtube, has g...A great new course for beginners on youtube, has great content with short and crisp videos. Easy to follow. New content is getting added, So I suggest to subscribe.<br />https://www.youtube.com/watch?v=BGWVASxyow8&index=18&list=PLFAYD0dt5xCzTQHDhMPZwBoaAXWeVhZzgSelva Prabhakaranhttp://www.blogger.com/profile/05519694374996247829noreply@blogger.comtag:blogger.com,1999:blog-8909074830238091680.post-56990377886806817392014-05-06T20:38:28.865+10:002014-05-06T20:38:28.865+10:00how to find relative importance index using spss f...how to find relative importance index using spss for my likert scale data??Harrison Yanhttp://www.blogger.com/profile/12366111009273933160noreply@blogger.comtag:blogger.com,1999:blog-8909074830238091680.post-56099438351326313502014-05-02T15:27:53.752+10:002014-05-02T15:27:53.752+10:00I guess you could use the traditional graphics dev...I guess you could use the traditional graphics devices like png and pdf<br />http://stat.ethz.ch/R-manual/R-devel/library/grDevices/html/Devices.html<br /><br />Otherwise, I'm not sure. I guess you could scan the knitr options, but I haven't seen anything designed to do this: http://stat.ethz.ch/R-manual/R-devel/library/grDevices/html/Devices.htmlJeromy Anglimhttp://www.blogger.com/profile/12949204812496382042noreply@blogger.comtag:blogger.com,1999:blog-8909074830238091680.post-74402952848704416142014-05-02T13:08:43.370+10:002014-05-02T13:08:43.370+10:00Great cheat sheet for knitr newbies, thanks! I hav...Great cheat sheet for knitr newbies, thanks! I have a follow-up, though. Each chunk generates a .png, which default name is the name of the chunk. For example,<br />```{r ChunkName}<br /> p<-ggplot(ds, aes(x=varible1))<br /> p<-p+geom_bar()<br /> print(p)<br />```<br />will produce a .png named "ChunkName.png"<br /><br />If there are a several graphs to be produced by the same chunk, they will be automatically ordered. So<br />```{r ChunkName}<br />years <- 1997:1999<br />for (year in years){<br /> p<-ggplot(ds[ds$year==year,], aes(x=variable1))<br /> p<-p+geom_bar()<br /> print(p)<br />}<br />}<br />```<br />will produce 3 graphs: "ChunkName1.png", "ChunkName2.png" and "ChunkName3.png". However, I'd like to name the pngs myself, tying them to some automatic variable (like year, in this example), so that it produced something like<br />"ChunkName_1997.png", "ChunkName_1998.png" and "ChunkName_1999.png". <br /><br />Any ideas how to override the defaults? <br /><br /><br />Андрей Ковальhttp://www.blogger.com/profile/14264243871276423056noreply@blogger.comtag:blogger.com,1999:blog-8909074830238091680.post-16398006946768038312014-05-02T00:03:17.564+10:002014-05-02T00:03:17.564+10:00Dear Jeromy,
is there a chance that you could hav...Dear Jeromy,<br /><br />is there a chance that you could have a look at my question about modeling nominal variables in JAGS ?<br /><br />http://stats.stackexchange.com/questions/95929/bugs-jags-for-nominal-response-model<br /><br />thank you very much<br /><br />J.k1111http://www.blogger.com/profile/11449275035410259115noreply@blogger.comtag:blogger.com,1999:blog-8909074830238091680.post-84116919026177307512014-04-26T14:52:14.291+10:002014-04-26T14:52:14.291+10:00That's what this post is about. What do you wa...That's what this post is about. What do you want to know?Jeromy Anglimhttp://www.blogger.com/profile/12949204812496382042noreply@blogger.comtag:blogger.com,1999:blog-8909074830238091680.post-75939253518365646032014-04-26T14:51:15.047+10:002014-04-26T14:51:15.047+10:001. r means correlation; r12 means correlation betw...1. r means correlation; r12 means correlation between variable 1 and variable 2<br /><br />2. N means total sample size<br /><br />3 and 4. the symbol means square rootJeromy Anglimhttp://www.blogger.com/profile/12949204812496382042noreply@blogger.comtag:blogger.com,1999:blog-8909074830238091680.post-29638797646702761342014-04-25T09:16:35.793+10:002014-04-25T09:16:35.793+10:00Concerning Hotelling's T-test for "corre...Concerning Hotelling's T-test for "correlated correlations", I have some questions about the formula<br />1. r: what does "r" mean like r12?<br />2. df=N-3: What does "N" mean? Does N mean the sample size?<br />3. √ [N-3]: What does "√" mean? <br />4. √ 2: What does "√" mean?<br />Chun-Lan Changhttp://www.blogger.com/profile/14343630378681915325noreply@blogger.comtag:blogger.com,1999:blog-8909074830238091680.post-880293574348554992014-04-25T09:14:22.229+10:002014-04-25T09:14:22.229+10:00Concerning Hotelling's T-test for "corre...Concerning Hotelling's T-test for "correlated correlations", I have some questions about the formula.<br />1. r: what does "r" mean like r12?<br />2. df=N-3: What does "N" mean? Does N mean the sample size?<br />3. √ [N-3]: What does "√" mean? <br />4. √ 2: What does "√" mean?<br />Chun-Lan Changhttp://www.blogger.com/profile/14343630378681915325noreply@blogger.comtag:blogger.com,1999:blog-8909074830238091680.post-61859015692889431452014-04-24T19:11:39.611+10:002014-04-24T19:11:39.611+10:00If there are three quantitative variables: x, y, a...If there are three quantitative variables: x, y, and z, how to perform dependent correlation analysis? Thanks.Chun-Lan Changhttp://www.blogger.com/profile/14343630378681915325noreply@blogger.com