# Tagged Questions

Mathematical re-expression, often nonlinear, of data values. Data are often transformed either to meet the assumptions of a statistical model or to make the results of an analysis more interpretable.

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### Percentile Ranks in Matlab

I have 2 vectors of raw values. I need to do a percentile rank correlation and an ordinal rank correlation between them in Matlab. ...
324 views

### Is it necessary to log transform positively skewed DV’s even though I am using bootstrapping? [duplicate]

Possible Duplicate: In linear regression, when is it appropriate to use the log of an independent variable instead of the actual values? I am running a series of multiple mediation models. ...
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### Preprocessing of non-linear and censored variables

I now ran into two variables that give me problems. I know that I want to try to include them in the final model, but I'm unsure how the values should be treated in order to reflect the true nature of ...
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### Log transformation with negative values [closed]

This may for sure be a stupid question but suppose a model $$y = \alpha \times r^\gamma \times \varepsilon$$ the parameters $\alpha$ and $\gamma$ are of interst for me ...
2k views

### How to compute a new variable that is defined by two categorical variables using SPSS?

I have a questionnaire with a part (a) and part (b). It looks like this: ...
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### How to transform data to normality?

We have financial some data (500-1000 samples), which is not normally distributed (well known fact from the literature). I have some ideas to do parametric transformations of this data (using some ...
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### How to compare data with difference in scale?

I am working with the data obtained from a travel survey from a town. I have the data from mean of trips made by different travel modes on the day of the survey. From a national suevey I have got data ...
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### What do you call adding zeros to a table of frequency counts of consecutive integers where the given integer does not occur

I am wondering what the proper term for this is: Turning this: ...
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### Nonlinear regression: best transformation when getting very different parameter estimates

Disclaimer: Statistics is not my strong side, so if my question is nonsense I apologize. I'm a beginner, but really wanting to understand this. My question is: why do I get so widely different ...
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### Slope error after transform?

I have a slope $b = 0.9543$ with std err $s_b= 0.1172$ . I compared this to a theoretical slope $\beta_0 = 2$, which is significantly different at the level $p = 0.00044$ (df=4). But what I ...
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### Transformation to normality for random variables with different locations

I have a (potentially infinite) sequence of random variables $X_i$, with $i = 1, 2, \dots$, which have the same distribution (in terms of "shape"), but different locations. I have a sample of size ...