Tagged Questions

10
votes
2answers
396 views

How are regression, the t-test, and the ANOVA all versions of the general linear model?

How are they all versions of the same basic statistical method?
2
votes
1answer
65 views

Advice on the statistical analysis of clinical data using summary statistics, t-tests, ANOVA, and linear regression

I need some help with the statistical analysis of a study of a particular surgery to remove a particular cancer. I am using the statistical program R to conduct my analysis. My data are saved in the ...
0
votes
0answers
39 views

Evaluate Quantile Regression results and t-stats at different levels.

I have a few questions regarding quantile regression and how to interpret the results. I have several independent variables and I want to figure out which combination of variables have the highest ...
2
votes
0answers
162 views

t-test vs. comparing regression coefficients

I understand that independent t-tests compare two means and establish whether they are statistically different from one another. If I want to compare whether there are statistical differences in the ...
0
votes
0answers
250 views

How to quantify the significance of the difference between two z-scores?

I have one sample and several features. I calculate a z-score for various features, and for various combinations of features. Is there a way to quantify the significance of the difference between ...
0
votes
3answers
153 views

SPSS Interesting analysis types: Beyond the basics

Following a previous question I made I'd like to state once more that this is my first attempt at analyzing data with SPSS. I have encoded and transformed my data properly and I also used some of the ...
0
votes
1answer
343 views

Compare Regression Coefficients

I want to test if two regression coefficients from two separate regressions are significantly different from each other. In particular I want to test from the model $$ \begin{aligned} x1_{(t)} &= ...
0
votes
2answers
646 views

Proving Causality with t-test/regression

Earlier today I was discussing statistical analysis software with a colleague of mine. My colleague had primarily used SPSS in previous work for performing t-tests, anovas, manovas, and other ...
3
votes
0answers
205 views

Mean comparisons following multiple imputation

I need to do some simple mean comparisons between groups (basic F-test ANOVA) on data with missing values. I use R mice package for multiple imputation, but I can only pool results for the linear ...
0
votes
0answers
98 views

t-stats in OLS regression

Very basic question: suppose I run an OLS regression $Y$ ~ $X_1 + X_2$ and obtain t-stats of $t_1$, $t_2$ respectively. If $t_1$ >> $t_2$ (such as an order of magnitude larger), is it safe to conclude ...
0
votes
2answers
417 views

Two sample t-test vs regression

I would like to examine the difference in forecast error between year 1 and 2. The descriptive statistics show that the mean of forecast error is higher in Year 2 but the median is lower. Under what ...
3
votes
2answers
4k views

Minimum number of observations for multiple linear regression

I am doing multiple linear regression. I have 21 observations and 5 variables. My aim is just finding the relation between variables Is my data set enough to do multiple regression? The t-test ...
3
votes
3answers
580 views

Logistic regression versus t-test, which is better for this comparative-descriptive study?

Which type of test is most appropriate for this comparative-descriptive study? I have two groups of subjects (250 in each). My goal is to determine if the two subject groups are different and if so, ...
8
votes
3answers
8k views

Significance of coefficients in linear regression: significant t-test vs non-significant F-statistic [duplicate]

I'm fitting a multiple linear regression model between 4 categorical variables (with 4 levels each) and a numerical output. My dataset has 43 observations. R gives me the following p-values from the ...
2
votes
1answer
114 views

Logistic / T-test p-values

I have Score data: integer ranging 0-100 which behaves normally on a QQ plot. The score is assigned to a subject which is either Normal or Diseased and it differs between two. I tried 2 models: - ...
3
votes
2answers
2k views

Difference between t-test and ANOVA in linear regression

I wonder what differences are between t-test and ANOVA in linear regression? Is a t-test to test whether any one of the slopes and intercept has mean zero, while ANOVA to test whether all slopes ...
4
votes
1answer
640 views

What distributions are for the slope and for the intercept in linear regression?

In linear regression from a dataset $\{ (x_i, y_i), i=1,\cdots,N \}$, I wonder what distributions are for the slope and for the intercept? In Excel output, t-tests are used to tell whether the slope ...
7
votes
1answer
537 views

What are some good hard exemplary problem sets to work through to solidify my understanding of statistical concepts?

Over the years, I picked up many Statistics Concepts in by a variety of situations and means. I studied some Statistics maybe for a couple semesters almost 10 years back. But I also picked up concepts ...
26
votes
3answers
2k views

F and t statistics in a regression

In a multiple linear regression, why is it possible to have a highly significant F statistic (p<.001) but have very high p-values on all the regressor's t tests? In my model, there are 10 ...
17
votes
5answers
3k views

If the t-test and the ANOVA for two groups are equivalent, why aren't their assumptions equivalent?

I'm sure I've got this completely wrapped round my head, but I just can't figure it out. The t-test compares two normal distributions using the Z distribution. That's why there's an assumption of ...