Can you provide more information regarding the type of model you are working with. Are you looking for the fit of latent variable models, a regression model, etc.?

Dear Saurav Saha,

The parameters of fitness should be defined first, Similarly. fitness level should be targeted. Then look for SPSS software.

Dear Robert,

I am using regression model. 

Thanking You.

Dear Afaq,

Thank you so much. I have ddct value of certain genes against different different photoperiods. So I want to analysis the goodness of fit as well as level of regression. Can you suggest any other software except SDSS?

R is free and an excellent choice for linear models. You can use R-squared, analysis of residuals, etc. to look at goodness of fit. You can also compare models to see which fits the data best. Lastly, if you have "spare" data you can validate your initial model by seeing how well it fits an independent dataset.

Dear George Stata statistic pack is a excelent software, it has a lot of windows with statistical proofs for taste the goodness of fit of any model. Mario

Chi-Square Goodness of Fit Test

When an analyst attempts to fit a statistical model to observed data, he or she may wonder how well the model actually reflects the data. How "close" are the observed values to those which would be expected under the fitted model? One statistical test that addresses this issue is the chi-square goodness of fit test. This test is commonly used to test association of variables in two-way tables (see "Two-Way Tables and the Chi-Square Test"), where the assumed model of independence is evaluated against the observed data. for more plz read at following link

.

http://www.stat.yale.edu/Courses/1997-98/101/chigf.htm

Dear Ali,

Thank you for your valuable answer.  If I will give you some raw data of my experiment , please help me how to calculate goodness of fit? Actually I want to use any Statistical software.

Dear Ali,

I am sending you some the raw data of my experiment, please help me how to calculate the goodness of fit. If is it possible then kindly tell me step wise process how to calculate.

Thanking you.

Dear Saurav Saha,

I Have attached one article read it.

http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.509.4258&rep=rep1&type=pdf

Dear Mogili Sir,

Thank you so much, but I want to do the Goodness of fit calculation through MS Excel. If I will send you raw data can you help me how to calculate goodness of fit ?

Thanking you.

One-Way Tables (Testing Goodness of Fit)

Author(s)

David M. LanePrerequisites

Chi Square Distribution, Basic Concepts of Probability, Significance Testing

Learning ObjectivesDescribe what it means for there to be theoretically-expected frequencies

Compute expected frequencies

Compute Chi Square

Determine the degrees of freedom

The Chi Square distribution can be used to test whether observed data differ significantly from theoretical expectations. For example, for a fair six-sided die, the probability of any given outcome on a single roll would be 1/6. The data in Table 1 were obtained by rolling a six-sided die 36 times. However, as can be seen in Table 1, some outcomes occurred more frequently than others. For example, a "3" came up nine times, whereas a "4" came up only two times. Are these data consistent with the hypothesis that the die is a fair die? Naturally, we do not expect the sample frequencies of the six possible outcomes to be the same since chance differences will occur. So, the finding that the frequencies differ does not mean that the die is not fair. One way to test whether the die is fair is to conduct a significance test. The null hypothesis is that the die is fair. This hypothesis is tested by computing the probability of obtaining frequencies as discrepant or more discrepant from a uniform distribution of frequencies as obtained in the sample. If this probability is sufficiently low, then the null hypothesis that the die is fair can be rejected.For more plz read at following link.

Regards

http://onlinestatbook.com/2/chi_square/one-way.html