# ttest

1. ### T-Test help!! Which tail and which type.

I'm currently investigating the effects of a strain on fungus on plant growth. So I have tested the same species of plant under 7 different conditions. 1 = Control (no fungus) 2, 3, 4 = Fungus A at 3 different concentrations. 5, 6, 7 = Fungus B at 3 different concentrations. I am going to...
2. ### Which T-Test tails/types do I use in Excel?

Hi everyone, I apologise in advance in if I have posted in the wrong thread. I am trying to perform a t test here where I am using the AssessMark against the SuprtScore, QualScore, SatisfScore and SysBen columns. As I am using excel to perform the computation, I am not so sure if I am doing it...
3. ### What analysis is best for my research

Hi all, I'm currently doing my masters thesis about blood pressure monitors. I'm compairing them on repeatability using a simulator. Now i have 5 different devices with each 3 simulations x 85 measurements. (Simulations are High blood pressure, low and normal) I did the basic thing like look...
4. ### Comparing two samples with not independent observations within each one

Hi, I would appreciate your advice. I have the following experimental design: I measure the heartbeat of a person while he/she listens to music. The hypothesis is that the louder music will result in higher heartbeat rate. So, a subject listens for 30 min classical piece while measuring...
5. ### Constructing intervals VS hypothesis testing?

Hi folks, let me briefly anticipate that I am a total newby to the magical world of statistics. So, right now I'm preparing for a "quantitative methods for economics" test, but while doing my exercises I found myself wondering about what could be very stupid things. here's the thing: I had...
6. ### T Test word problem! HELP

im going crazy trying to figure out this problem; please help! 2. Assume that we drew a random sample of 300 women who had recently graduated from USC. All of these women worked full time in 2018. They earned an average salary of $42,167 (s.d. =$26,413). Based on data from the US Census...
7. ### A Hypothesis testing problem

I have been facing some doubts regarding the problem given below. Firstly, if this problem is a Z-test or a T-test? Secondly, what should be the standard deviation ? sigma =? Here is my attempted solution, Please help.
8. ### Comparing results of a promotion camapign: Control vs Treatment Sub-Group

I'm looking for some clarification on the correct way to test the difference between groups. At my company we ran a promotional campaign for credit card customers with a chance to win a prize. We took all customers who had a credit card and divided them into a Control Group and Treatment Group...
9. ### What is the appropriate test for testing the difference between 3 variables?

Hi all, I have a group of n subjects. Each subject has 3 measurements x, y, and z. 1-What kind of statistical analysis I should perform to see if those three measurements are significantly different or not? (units are the same for all variables) 2- I can tell by visual inspection that...
10. ### ttest for comparison of group means from pooled samples

Hello, I have results from an experiment where a number (n=50) of biological samples were pooled together with a single measurement of chemical level taken for control and experimental pooled sample. How would I calculate the significance of difference between these measurements, where I only...
11. ### TTEST vs Logistic Regression

I have seen some posts here with the same title but I believe my problem is different: I am unsure whether to conduct a 2 sample ttest or a logistic regression because I am unsure of which variable should be my outcome and which should be my predictor variable. The problem: There are 5...
12. ### Performing multiple t-tests on different variables between the same two groups

Hey everyone I would like to perform multiple t test on different variables ( let's say A B C D E ) in two different groups ( 1 2 ) and test if the means, variance, kurtosis is significantly different between A1 and A2, B1 and B2 etc. How do you think I should go about this in R or SAS ...
13. ### Stata Unbalanced Panel Data - which ttest should I use to compare means?

Hi, Apologies if this question is very basic but I have spent hours looking online and in forums such as this one for an answer and I am still unsure. I have an unbalanced panel data set of a few thousand firms, for the years 2002 to 2008. I have looked at the mean values for the audit...
14. ### Which statistical analysis needs to be run ? ANOVA/Paired T-Tests

So i trying to figure out what analysis i need to use,but im a tad stuck. Im doing a pre and post test design. So a primary school with a programme , measured by the questionnaire before and after . Then there is a control group primary school without a programme , measured by a...
15. ### T- Test output

Hi, I am conducting an independent T-Test in SPSS (users and non users) against a range of independent variables. I now have found significance in one of my variables (perceived compatibility) the results are; t(49) = -3.357, p=.002. Am I right in thinking that because my t value is negative...
16. ### What to do if sample size is too big? (ttest)

So I'm running ttests for a descriptive statistic table and all my results are significant, but I"m concerned that the sample size is too big 3,880 obs for each of the two groups. (This is bank data by qtr appended into one file.) I understand that the large sample size is probably making...
17. ### Hypothesis testing - ttest difference in 1-tail versus 2-tail

Hi, I am runnings some Ttests, and when I conduct a one-tailed test to see if Variable "a" is greater than Variable "b" the result says to reject the null hypothesis, but when I conduct a two-tailed test to see if Variable "a" is different than variable "b" the result says not to reject the...
18. ### t-tests vs chi square test/Fisher's exact test

Hello forum friends! So I have been using excel to compare if two groups are statistically significantly different. My null Hypothesis is that these two groups are the same (or that there is no difference between groups). When comparing my Hispanic population vs non-Hispanic population...
19. ### Using ttest instead of R-Squared for acceptance

I have independent variable X and dependent variable Y. I am trying to compare the predictive power of a number of regression based models. For each model I obtain a R-Squared value. Also for each model I can obtain predicted Y (call it Y_new). What if I perform ttest on (Y_give - Y_new) to test...
20. ### Correlation Between Unpaired Data?

What type of statistics compares or finds correlation of unpaired data? I'm assuming an XY scatter plot wouldn't work. I'm also assuming a t-test or Krus Wallis would be more appropriate? For example: Group A: 1, 3, 5, 1, 4. (n=5) and Group B: 5, 6, 7, 1, 2, 5, 6. (n=7). Total number of samples...