# goodness of fit

1. ### Reduced chi-squared test fit goodness

In Origin Pro 9, I made 2 linear fits (y = kx + b). For example, I chose equation y = x + 10. In one case, I set experimental following points: x =1, y= 11 x = 2, y = 12 x = 3, y = 12.8 x = 4, y = 14.1 x = 5, y = 15 x = 6, y = 16 x = 7, y = 17.3. In another case, I set: x = 1, y = 10 x = 2, y =...
2. ### Python PowerDivergence

I am no statistician but I was asked to provide some quantification of the goodness-of-fit of a theory. This theory only uses one parameter and that parameter was fixed (not a fitting parameter), so the values are predictions. The plot of the fitting is here: Here are the results from...
3. ### Goodness of fit tests

Hi there, Adding to my previous questions: 1. Why do I need goodness of fit test? I mean when I get a set of data should I always suggest a distribution for it and then do test the goodness of fit for this hypothesis? or it comes in sequence of :1.estimation 2.goodness of fit 3.hypothesis...
4. ### Goodness-of-fit test

I have a question regarding goodness-of-fit tests. A general rule of thumb with the chi-square test of goodness of fit is that (1) no more than 20% of your expected frequencies can be less than five, and (2) none of your expected frequencies can be less than one. However, I am dealing with a...
5. ### Goodness of Fit Tests - are they really good?

Hi, after some time of using goodness of fit tests without really thinking about them, I came to this curious question: Normally, it is recommended to have a Null hypothesis which you want to reject. (I.e. the opposite of what you want to show.) However, in Goodness of Fit this is not the...
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### Goodness of fit measure for a MNL model

Hello! I have carried out MNL regression with the same model among different samples and I now need to compare the results against each other. In order to do that I'd need a single indicator that describes the goodness of fit of each model. Does something like this exist for MNL regression...
7. ### Goodness-of-fits tests.

I honestly have no idea where to even start in this assignments. Any type of ell would be greatly appreciated. I can easily do the problems given in different forms but word problems have never been my strongest. According to the following distribution (digit, probability): (1, 0.301) (2...
8. ### Multinomial Logistic Regression

I have run a multinomial logistic regression looking to see if being a member of two different groups predicts group membership to 5 categories. I have attached the output – I am not sure if it is a problem or not if the Goodness of Fit test as zero degrees of freedom and no significance values...
9. ### How to analyse deviance (GLM in R)

Hi! This might be quite basic, but how do I analyse the fit of my GLM from the deviance? In the summary of my model, I get a deviance of 140.1 (df.resid = 52). Can I tell from these numbers, if the fit is acceptable? Thanks in advance for any replies!:tup:
10. ### Fit of generalized linear model (Poisson distribution)

Hi guys Can anyone tell us how to evaluate the fit of our generalized linear model with a poisson distribution? We can't really tell if the model is a good fit or not. Do you use the deviance to answer this question? If so, what does it tell us in the following example? Thank you in advance...
11. ### Comparing 2 best fit lines for 2 halves of a data set

I have a data set with ~200 coordinates plotted on a scatter plot. I can either use the data set as is, or split this plot into two data sets along a line x = 0.2 (so that the first new set will have the range -1 to 0.2, and the second will have the range 0.2 to 1). I then create a best fit line...
12. ### Goodness of fit (QIC) in Generalized Estimating Equations (GEE)

Hi, I have a question concerning goodness of fit which is measured as QIC in the GEE analysis: In general I learned that if QIC decreases the change in the model was for the better. => Decrease in QIC = Good However, I am trying to add new model terms and for all of them QIC...
13. ### Theoretical questions about Chi goodness of fit & Fisher's Exact tests

Hello statisticians, My main questions are; 1) For a Chi goodness of fit test, which effect size do you use? I am being told Cramer's V, Phi, Omega and W! (There seem to be a lot more answers for a Chi association test, but not for a Chi goodness of fit) 2) Can you use an Odds Ratio...
14. ### Help on analysis of simulation results

Hello. I am performing simulations on a project (changing durations of activities randomly from lognormal distribution). I perform 100 simulation runs with different acitivity durations on the same project. Afterwards, I insert additional activities in the project schedule and run 100...
15. ### Using estimators for goodness of fit test

This is a practice question I came across when dong some goodness of fit test examples.A company sells cloths by mail order.The size of clothes is defined by hip size; thus the height of customers of a particular customer may vary considerably. Data set of heights sent in by customers of size...
16. ### Obtaining sample variance from grouped data for goodness of fit test

This is a practice question I came across when dong some goodness of fit test examples.A company sells cloths by mail order.The size of clothes is defined by hip size; thus the height of customers of a particular customer may vary considerably. Data set of heights sent in by customers of size 18...
17. ### Goodness of fit test for a normal ditribution

In the example from a site I was trying out http://www.cimt.plymouth.ac.uk/projects/mepres/alevel/fstats_ch5.pdf this problem in page 107 about Goodness of fit test for a normal distribution.Question is about analysis of fat content of hambergers. I understand that we need to have the two...
18. ### Goodness of fit test for exponential distribution

The given data below shows the time in intervals in seconds between successive white cars in flowing traffic in an open road.Can these be modeled by an exponential distribution. I am computing the expected frequencies by calculating the probability at each interval.Under null hypothesis as...
19. ### Goodness of Fit test with 2 sets of data, not sure how many degrees of freedom I have

I have two data sets, one with 1000 observations and the other with 50. The observations can equal A, B, C or D. Now using the first set of data I calculate the probabilities P(A)=(freq of A)/100 and similarly for P(B),P(C) and P(D). I now want to use these probabilities to model the second...
20. ### Validation of survival data / models

Hello, I'm currently analysing a couple of survival data with parametric survival analysis (AFT and PH) in STATA 12. I'm investigating different parameters and different distribution function. To chose the best available model I'm using an information criterion such as AIC or BIC. So far so...