t-test

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

One variable is injuries yes/no, the other variable is rating how much in control they felt (0=none,100=total). Basically if injuries causes low levels of perceived control. I have to use a t-test, but there are so many and I really don't know which one.

Hello fellow statisticians, Problem definition: I need to test whether the difference between the "mean" utilization metrics of two machines is statistically significant. Given Data: Utilisation data is available for two machines for more than 100 days. Therefore, the mean, standard...