t-test

  1. J

    Correct statistical analyses

    Hello, I have a project I'm working on and I am unsure about which statistical analysis would be correct. My professor is not helping much and I am terrified of failing. I have two groups that I want to compare their results after treatment. One receives treatment and another group doesn't...
  2. S

    Comparing outcomes of two treatment groups: t-test/Mann-Whitney U versus regression

    Hi all - I'm a student and had a question about statistical analysis. I'd like to compare post-treatment outcomes between two groups: group A who received a traditional drug (n = 200), and group B who received a newer drug (n = 100). Some post-treatment outcomes are continuous, whereas others...
  3. Z

    Correlation signficance

    I would appreciate help in checking whether my attempt to decide whether my correlations are significant is correct – I suspect not, and would welcome a correct set of functions. After computing the correlation of two arrays, for example: JL50: CORREL($QW$5:$QW$46,JL$5:JL$46) = 0.4084, I then...
  4. L

    Should I use Bonferroni correction?

    Hi. I‘m analzying the influence of Yoga on stress adadption and work related stress. I tested the differences of work related stress between pretest and posttest in the experimental group by a paired t-test. I also tested the differences of stress adaption between pretest and posttest in the...
  5. P

    2-sample t-test shows no equal means, can I still compare capabilty analysis and Ppk's?

    I want to compare two categorical situations (old vs. new part in a machine) with the continuous CTQ, the y-variable. In order to compare the 2 situations, I found the proper distribution and compared the two Ppk values. I saw a significant difference in performance (the new part was +-3 times...
  6. P

    Manova, Hotelling's T^2, t-test or Anova?

    Hello, For my final thesis, a few questions arose during the pre-registration process and I would be very happy to receive answers. I will conduct an experiment with three groups (1, 2, 3) and 3 dependent variables (a, b, c) to find answers to the following 2 hypotheses: H1: M(2) > M(1) -...
  7. M

    T-statistics

    Hi, I am trying to calculate t -statistics (formula below). I am not sure if I need to use a one-tail or two-tail test. I have attached an excel sheet with the calculation (i used t.inv.2t - line q25). The issue is; I am not getting the expected value which is 0.113976896 (the value I am...
  8. W

    Paired t test unequal sample sizes?

    I want to find if there's a significance between the two levels average mean values from my dependent variable "X," which are "High X" and "Low X." High X (85 items) + Low X (65 items) = X (150 items) Both have unequal sample size, but they're from the same group "X." I opted for paired sample...
  9. H

    Do I need a two-way MANOVA test?

    I am testing for differences between 3 groups. I have 2 dependent variables which are continuous data. However, I am confused about my independent variables and if a two-way MANOVA test would be suitable. My three groups are Rural, Semi-rural and Urban (3 groups). For each group I am testing...
  10. C

    Question: Single person - T-test?

    Can you look at improvement in scores across two time periods, if you have hundred of data points but they are all from a single individual. Can I do a t-test to compare the indvidual's scores over one period to the same individual's scores over a later period? I've never encountered anything...
  11. F

    What statistic method should I use for this situation?

    Imagine if I have 3 types of parts A, B, C and there is one parameter to judge the quality of the parts under certain condition, but this parameter is not that reproducible. For example, under certain condition, A, B and C will have different value of electric surge. I understand if we collect...
  12. J

    Why does the “linear regression t-test” return a p-value (two-tailed) from regression that is twice the p-value from ANOVA? (Binary predictor)

    I'm using the "linear regression t-test" guide at https://stattrek.com/regression/slope-test.aspx The guide shows calculating t =b1/SE, where b1 and SE are provided by the regression function (here lm() - using R.) The guide shows the p-value gets doubled as this is a two-sided test...
  13. I

    Constant sum question - results analysis

    I ran a study with a constant sum question: participants had to divide 100 units (I called the units USD) between 5 possibilities. In other words, they had to bet on five possibilities: 1 object out of 5 has a property vs. 2 objects out of 5 have a property vs. 3 objects out of five have a...
  14. D

    Help with my research question analysis

    Hi everyone, I am a doctor working on a project investigating an intervention we have been using in the intensive care unit in my hospital for treating Covid patients. I am collecting data on all the patients who have been admitted and look at whether they have had this intervention, whether it...
  15. H

    Testing for similarity between countries

    For my thesis, I am looking at the effect of environmental controversies on the profitability of Chinese and European firms. As part of my exploratory analysis, I have to check whether or not the European countries are similar enough to consider them as 1 group. I collected data on economic...
  16. L

    chi square or unpaired t-test? (or other??)

    Hi - I am looking to compare two groups - mobility activity after surgery. Group 1 - is a 'low ability' (ie, very old, frail) Group 2 - is 'high ability' (able to move around before surgery). The numbers in each group are NOT means, they are simply counts of patients. Ie, on the first day, 37...
  17. C

    choice of t-test

    Hello I have been presented with some data and, being a bit rusty on my statistics am unsure whether I have used the correct t-test. The data shows the results of of farmer trials; 22 plot-pairs, with each plot-pair containing a control and a test. Based on my understanding, the correct t-test...
  18. K

    t-test or ANOVA? urgent

    Hi, I am looking for advice about which stat test to use in my data analysis for our psychology class. We collected data on reasoning tests scores. I have two groups of participants 1) non-bilingual 2) bilingual and dependent variable in the form of reasoning scores in 1) spatial reasoning...
  19. J

    Thesis Help Request - Hypothesis Testing

    Hi I am doing an event study and my null hypothesis is CAAR=0 and alternative is CAAR does not equal 0 (2 tailed t-test). CAAR is cumulative average abnormal returns. Can a two tailed test be used to give directional conclusions, e.g. if the CAAR value is 1.5% and is statistically significant at...
  20. M

    Sample size when adding two means

    I want to compare a theoretical mean to a measured mean. But I determine this theoretical mean from adding two measured means. For example, let's say I want to determine if mixing a shade of white paint with a shade of black paint yields a particular gray paint (let’s pretend I can quantify...