Linked Questions

3
votes
1answer
4k views

Understanding a Quantile-Quantile Plot [duplicate]

I must have generated at least 5 Q-Q plots until now when trying to fit my data into a known distribution but I just noticed something that I could not understand. In the figure shown below, from what ...
0
votes
1answer
3k views

How would you judge this qq plot? Distributional assumptions? Outliers? [duplicate]

Looking for some help. Here's my qq plot. I already deleted the most extreme outliers, but some remain. Also, what about the distributional assumption?
1
vote
1answer
3k views

How do I know what side is skewed? [duplicate]

If I look at a quantile plot comparing normal distribution and other data, and some of the points lie below or above the line, how do I know what that represents? What I am asking is - how do I know ...
1
vote
0answers
2k views

Interpretation of qq plot and normality [duplicate]

I am doing some multivariate regression. When I plot QQnorms to check my model assumptions (errors normally distributed), I get Question: How do you interpret the above? Are the normality assumptions ...
0
votes
0answers
519 views

Good explanation of the QQ-plot algorithm? [duplicate]

Anyone know a good explanation of the QQ-plot algorithm? http://www.biostat.au.dk/teaching/basicbiostat/F2014/qq-plot.pdf, p.2. has the only one I've found and it's a bit unclear to me (particularly ...
3
votes
0answers
470 views

Understanding output of qqPlot in R [duplicate]

I was trying to understand qqPlot and found that for finding Normal Distribution of data , qqPlot is a good tool. Then I ran 2 set of examples and got the following output where in both the case, all ...
1
vote
0answers
320 views

What does this QQplot tell us? [duplicate]

For a multivariate data set, I test normality on the marginals, and I get plots like above. That's not my actual plot.... mine is not that obvious, the middle part is actually quite straight.... but ...
1
vote
0answers
190 views

Does this normal distribution plot show a good fit? [duplicate]

I am not well acquainted enough to judge this well. This plot was obtained from normplot in Matlab. There is a good linear fit although the tails are concerning. Does my data follow a normal ...
0
votes
0answers
124 views

Normal QQ-plot interpretation [duplicate]

I seek help interpreting this qqplot. Am I correct that data points near the mean are reasonably normal, but data points away from the mean tend to be too far off, therefore the data is fat-tailed? ...
0
votes
0answers
81 views

QQ Plot Interpretaion [duplicate]

I have a daily time series and when trying to check for normality I am getting the QQ plot below. Any ideas as to what is the plot saying about my data?
1
vote
0answers
72 views

QQ-Plot interpretation [duplicate]

I am working with a dataset (900 observations) and have the following normal QQ plot in R: Seeing that the QQ-plot little bit strange, what could I infer about the underlying distribution? It seems ...
0
votes
0answers
26 views

How to interpert a qq plot [duplicate]

I'm a little confused about how to interpert this qq plot. The huge gap between the values makes me think it's not the best normal distribution, but i'm not sure how to draw a good conclusion out of ...
98
votes
1answer
80k views

Interpreting plot.lm()

I had a question about interpreting the graphs generated by plot(lm) in R. I was wondering if you guys could tell me how to interpret the scale-location and leverage-residual plots? Any comments ...
50
votes
5answers
16k views

Interpreting QQplot - Is there any rule of thumb to decide for non-normality?

I have read enough threads on QQplots here to understand that a QQplot can be more informative than other normality tests. However, I am inexperienced with interpreting QQplots. I googled a lot; I ...
57
votes
3answers
34k views

Box-Cox like transformation for independent variables?

Is there a Box-Cox like transformation for independent variables? That is, a transformation that optimizes the $x$ variable so that the y~f(x) will make a more ...

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