outliers

  1. L

    Investigation outliers, could data mining be a solution?

    Hi everyone, This is my first post. :wave: I am currently working on a project to investigate the reason for why these providers are outliers on the dataset on a whole. I am finding it very tricky to find statistical methods that "investigate" outliers- as in show you why they are outliers...
  2. L

    Outliers and correlation

    Hi all Im working on small size sample (17) . and need to do correlation for alot of prameters my questions is : -is removing the outliers is the only thing I should do to prepare the my data for doing correlation ? What about the transformation ? when I should use it ? - What is the...
  3. B

    Assigning outliers in very few datapoints

    Hi, I'm a geology PhD student and i have a problem with making my dataset statistically robust. I'm measuring element concentration of my samples using XRF. I have about 900 samples and measured each sample 3 times. Of course there is a variance in these 3 measurements belonging to each...
  4. noetsi

    Multivariate normality

    I know various methods of determing if the bivariate relationship of two variables are normal. But, as Dason has drilled into me, its multivariate normality (that is the normality of the residuals) that actually matters. I am not sure how to test for that. If you plotted the residuals into a...
  5. H

    cluster analysis and finding outliers

    This post is no longer up
  6. I

    can't detect outliers

    Hello, everyone, I am doing an assignment where i need to check the data on the statistical assumptions, I need to comment on the presence of outliers using histograms. in the picture below, the ones circled red - are they all outliers, or only the top one?...:confused: thanks!
  7. M

    Deleting outliers AGE varieble

    Hi all, I am conducting a bi-variate analysis of age groups (>40 years, 40-49, and 50-75) and basic demographic characteristics of women who had a breast cancer screening. The first thing I want to do is delete outliers (this seems logic to me). Some participants wrote that they are 1, 2 or...
  8. P

    Throwing out zeros from a faulty sensor

    I'm fairly new at stats. I have time-series data from a sensor. There are a lot of zeros in the data -- 70% of readings -- and those seem improbable physically. By visual inspection they seem to be faults, but the data otherwise looks like I expect it to. I plan to just throw away the zeros...
  9. F

    Winsorizing Panel data (eliminating outlier overall or across firms)

    We have a panel data consisting of about 1000 firms with each about 150 monthly observations (Returns and distress measures such as Z-score). In order to eliminate outliers we would like to winsorize at 1st and 99th percentile. However we are not sure if: a) to winsorize for each point of...
  10. S

    Detecting outliers in Negative Binomial Regression

    Hi all! I am conducting a negative binomial regression for my statistics project. I have been looking online about how to detect outliers but am not finding anything. I know that when using linear regression, the mahalanobis distance is used. However, since negative binomial regression is...
  11. C

    Citation needed for removing 3 Stdev outliers

    Hi, In a research paper, I had remove values that were 3 standard deviations away from the mean. The values simply didn't make any sense. I have been searching all over for a citation supporting the 3 standard deviation rule but haven't found much as most researchers don't seem to include...
  12. K

    Detecting outlier sample sites

    I have binomial frequency data for an allele associated with populations living in mountainous. These mountains run north to south where sites are nearly fixed for this allele and lowland sites to the east that lack the allele. At the south end of the mountains is a hybrid zone. Despite the...
  13. P

    Definitions of Time-Series Outliers

    I am using SPSS's Expert Modeler Option to Model a ARIMA model. I see that there is an option to have SPSS automatically detect various type of outliers. I get what the following outliers look like: Additive Level Shift Transient Seasonal Additive I think a Local trend outlier...
  14. B

    Computing how abnormal a data point is in a non-normal distribution

    Hi, folks. This is my first foray into posting on this forum, so apologies if there is a protocol I am unaware of. Let's say I have a binomial data set - m number of data points with a vaule of 0 and m number of data points with a value of 1. I have one data point (z) with the value of 0.5...
  15. D

    Help with Outliers

    Hello fellow scholars and researchers, I am a first year doctoral graduate student, and I could use a bit of advice. It's been a few years since my first graduate degree, and things are a bit rusty. :confused: I have been working with a dataset for a week now, and I recently read that...