t-test

1. 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...
2. 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) -...
3. 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...
4. 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...
5. 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...
6. 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...
7. 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...
8. 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...
9. 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...
10. 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...
11. 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...
12. 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...
13. 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...
14. 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...
15. 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...
16. 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...
17. What is the best statistical test/approach for pre- and post-intervention analysis?

Dear colleagues, We assessed several psychological measures (e.g. self-compassion scale, five-facets mindfulness questionnaire, satisfaction with life scale) before and after a Mindfulness-Based Psychoeducational Program for groups of people with acquired brain injuries. We would like to...
18. Paired test?

Hi, I have the following problem. In my experimental setup I have four tissue samples from the same animal in each experiment, two from one side and two from the other. The original plan is to apply a substance alone on a sample from one side and the substance mixed with the inhibitor on...
19. Choosing the proper statistical test for a lottery recommendation system

Dear friends, I'm now working on the recommendation system to recommend football match lottery to the users. The users may choose a match to bet arbitrary amount of money, e.g. $2,$4, or even \$20,000. I want to compare if two recommendation algorithms are different (or if one outperforms...
20. Test wanted for comparing algorithms

Study design Suppose I want to compare algorithm runtime performance (measured in seconds) of different algorithms for the same problem type. There are several problem instances for this problem type on which the algorithms are tested and performance is measured. Possible tests As far as I...