# t-test

1. ### Before/After- t-test???

Hello everyone, Kinda new to this forum. I need help in finishing off this project. So, my research question is whether an increase in the blood alcohol content (i.e., drinking alcohol) lead to a decrease in the mental capacity of performing basic tasks. In order to perform this research (and...
2. ### Regression for comparing two groups on one variable? And t-test with survey data?

Hi - I have two populations / groups that I need to compare on one variable. Now usually I would use a t-test or anova but ive been told that these are unable to be used with survey data in stata. Is this correct advice - can I not use a t-test or anova in stata with survey data? And would a...
3. ### What kind of test should I use?

I have 50 test items for 1000 students, each student answered 30 of them. I would like to find out whether the rate of correctness of items is different for students in 3 programmes, further I want to group the items favourable for each programme. Items are scored by 0 (wrong), 1 (partially...
4. ### t-test for large sample size - bike hire data

Hello everyone, I'm taking a graduate-level statistics course at the University of Glasgow which includes a methods assignment. The assignment requires us to correctly execute several statistics, including one and two sample t tests. To complete my assignment, I'm using a large dataset...

Hi all I am working on a project looking at ADHD in a large sample of adolescents. I am looking to investigate whether there are any differences between those in my sample who have previously had a diagnosis of ADHD and those who have not, on various ADHD rating scales. The rating scales...
6. ### 1-sample binomial for my research data?

Hi, Newbie here so I will try to explain as clearly as I can. I do research in the neuro field. I have a control group of neurons that I am analyzing for the presence or absence (binary) of a specific trait (let's call it trait A). I found that the control group have A 60% of the time. Now I...
7. ### Help with homework

On a homework assignment, I have a data set with the variables (in SPSS) 1) Age 2) Reactiontime (continuous) 3) drug (Placebo, or drug condition) 4) Amount of drug metabolites in their blood (continuous) 5) Subject number (1-20) 6) A median split dichotomous variable on drug levels (0...
8. ### Likert Survey -- Stat for comparing single items and sub categories

Hello, For my dissertation I am using an existing 50 item Likert survey. I am pretty sure I will use a t-test to determine if there are differences between my two groups for the individual items. What I am not sure about....is the 50 items are divided into 7 subcategories....to determine...
9. ### Help deciding paired vs unpaired t-test

Hi, I am analyzing an experiment in which protein levels were examined in two different strains of bacteria. Lets call them A and B. Three separate times bacteria A and B were grown up and their protein levels measured. Would each day's samples now be paired since they were grown on the same...
10. ### Statistical Analysis of Student Test Scores before and after an Intervention

Hello, Please help me ensure that I am conducting the proper statistical analysis. I am trying to determine if my student test score results are statistically significant after having applied a learning intervention. The data I am using are student test scores on TEST 1 from my 3 previous...
11. ### Different degrees of freedom when reporting multiple T-tests

Please refer to Table attached. This study compares those without a phobic disorder (n=83) with those with a phobic disorder (n=16) on Temperament scores. What I am confused about, is the reporting of the degrees of freedom: shouldn't the degrees of freedom all be the same number (i.e., n -...
12. ### Pair t-test with non-independent samples

Dear list, In my experiment, each subject of my sample has three time-series of data: tc_A, tc_B and tc_C. Using Pearson correlation within subject I calculate correlations between time-series: tc_A vs. tc_B, tc_A vs. tc_C and tc_B vs. tc_C. So, for each subject I get three correlation values...
13. ### Beginner questions: Clinical trial

Hi there! I am a medical student working on my PhD, and I am analyzing some data for a meeting. Since we don't learn much about statistics (at least not here in Germany :D), I have some beginner questions and I would be extremely happy if you could help me. The first question is the most...
14. ### Wilcoxon Signed rank test, Students's T-test, or a mixture of both?

Hello! For my dissertation I am looking at the temporal order of physiological and behavioural events before a voluntary action. I have 12 different repeated measures variables including: Time of intention (W), Readiness potential 1 (as measured by task A) Readiness potential 2 (task A), RPmax...
15. ### Which test should I use?

Hello, I'm writing my thesis and I'm clueless about which statistic test I need to apply ( is it T-test, Chi-text, Anova …), I will do my ststistics on SPSS. In my thesis I have 2 sets (=2 groups) of patients with the same disease, one group gets a specific treatment , while the second group...
16. ### Chi-Square vs t-test

Help! I am trying to compare observed education levels of a visiting group to the expected (known) education levels of the nation. These are my figures: Observed: 71% (have degree) 29% (no degree) Expected: 27% (have degree) 73% (no degree) If I use chi-square...
17. ### Paired or Unpaired T-test?

If I have traps set to capture a certain animal at night vs. during the day, would I use a paired or unpaired T-test? I'd be comparing the mean number of species 1 collected during the day with the mean number of species 1 collected at night (using the same trap). Each individual animal is...
18. ### Appropriate test for quantitative content analysis of one newspaper

Hi everyone, I am examining the differences in media coverage of homicide on the basis of the religion of the victim (bias). The sample is one newspaper over several years. The quasi-independent variable is religion (1 = christian, 2 = muslim).. This is not a dichotomous variable as...
19. ### t-test: very odd p value..

Hello, I have a strange p value and I am not sure how to interpret it: t = 5.3592, df = 46.353, p-value = 2.56e-06 Anyone know what to do with this? Thanks, Ted
20. ### Likert scale analysis - ordinal or interval??

Hi, I would appreciate some help so much as I feel I am going round in circles with every journal article I read! So I am currently trying to analyse the survey responses for my dissertation based on a 5 point likert scale. I gave surveys to two groups, a control and an intervention group...