1. ## Re: [help]interpretation needed please

Would you reject the hypothesis that the domestic output (x2) has the effect of 3 on y ?And why you using t test but not using normal distribution test?

this is the question three proper sorry my mistake

answer this please ... :S adn tell me why we use t test and not using normal distribution it is because that when large sample size we use t test ?? right?

2. ## Re: [help]interpretation needed please

and should we accept H0 becauase calculated t value of x2 is greater thn tabulated t value right? please...

3. ## Re: [help]interpretation needed please

Originally Posted by numerospy
Would you reject the hypothesis that the domestic output (x2) has the effect of 3 on y ?And why you using t test but not using normal distribution test?
Ah t and normal distributions are rather similar. The t distribution is used under the assumption of normality of error terms. Using t distribution allows more conservative (broader) confidence intervals. I think using the t distribution is advantageous when the sample is rather small (but the assumptions still hold). When the sample is large enough, using both distributions would provide rather similar results.

adn tell me why we use t test and not using normal distribution it is because that when large sample size we use t test ?? right?
No in a large-enough sample, both distributions would be OK (of course if the assumptions are met, in the first place). In smaller samples, the t distribution is better.

and should we accept H0 becauase calculated t value of x2 is greater thn tabulated t value right? please...
There is a critical value for the t statistics (the t value) which leads to a P value smaller than 0.05. This value is t = 1.96 for a 95% confidence limit. When the t statistic of the X2 variable is larger than the critical t value (in the case of X2, 3.2356 > 1.96), then the P value would become less than 0.05. When the P values gets less than 0.05, we reject the null hypothesis.

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numerospy (11-20-2013)

5. ## Re: [help]interpretation needed please

Originally Posted by victorxstc
Ah t and normal distributions are rather similar. The t distribution is used under the assumption of normality of error terms. Using t distribution allows more conservative (broader) confidence intervals. I think using the t distribution is advantageous when the sample is rather small (but the assumptions still hold).
You use a t-distribution when you have to estimate the standard deviation from the data itself. So in practice that means pretty much always.

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noetsi (11-18-2013), numerospy (11-20-2013)

7. ## Re: [help]interpretation needed please

About your first question, is it good or not: Well you can judge the quality of the regression based on values such as the adjusted r-squared. However, as noetsi pointed out, the question could be asked in a better way: If the regression has a proper accuracy or not (rather than is it good or bad). Anyways, the adjusted r-squared is a key statistics in judging the regression. Based on its value, it seems that your regression is rather accurate (or good). Note that this can be refuted by more sophisticated discussion about the merit of the adjusted r-squared, in the first place. But be sure that this value is an important value that has its implications in judging a regression.

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numerospy (11-20-2013)

9. ## Re: [help]interpretation needed please

Dason's point is a very good one it took me a long time to find in the literature. Many accounts of t versus z scores deal with distributions or sample size not if you know the SD (something which will almost never be the case in real life). I am not sure how in practice you could ever know it since even past studies could involve populations that changed since the analysis was done.

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numerospy (11-20-2013)

11. ## Re: [help]interpretation needed please

About the second question: How you interpret the beta 2 and beta 3 coefficients?

Well, you can interpret them this way: The variable X2 has a significant positive correlation with the outcome variable (y), when other variables are controlled for. The variable X3 has a negative correlation with the outcome variable, however its effect is not significant.

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numerospy (11-20-2013)

13. ## Re: [help]interpretation needed please

The third question asked in your first post in this thread was not clear to me.It is talking about -2 effect on y or +3 effect on y. I think your teacher or source should be first clarified... The thing rejected in such cases is not usually "if something is not -2 or +3". It is usually: "if something is not zero or not". I think there is no sufficient information for answering the third question, or that it is written incorrectly.

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numerospy (11-20-2013)

15. ## Re: [help]interpretation needed please

Originally Posted by noetsi
Dason's point is a very good one it took me a long time to find in the literature. Many accounts of t versus z scores deal with distributions or sample size not if you know the SD (something which will almost never be the case in real life). I am not sure how in practice you could ever know it since even past studies could involve populations that changed since the analysis was done.
I was talking about the theoretical perspective I knew. I agree with Dason's valuable comment (and yours too) about the practical issue of normal distribution. But still I thought that the t distribution would become normal distribution in larger enough samples (I mean the infinity which might be 30 according to Dason's prof). But anyways, t is the star here.

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numerospy (11-20-2013)

17. ## Re: [help]interpretation needed please

thank you so much i have no words to say thanks to you guys alot thanks again these steps helps me alot and i am now able to solve my assignments by your helps and things you provide here i love you all and thank you so much guys thanks thanks again....

18. ## Re: [help]interpretation needed please

I am so glad we could be of some help.

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numerospy (11-20-2013)