normal distribution

Hello everyone! Is it true that when your sample is more than 30 people, you can do parametric tests, even though your sample may not follow the normal distribution? In my research I have 400 people as a sample, not following normal distribution and someone told me that I can do parametric...

Hello friends of the forum I have the following doubt ... If I have a sample of only 24 discrete data, how can I prove that these data follow a normal distribution? When I enter the data into a specialized software, the software tells me that the sample fits a normal distribution, but I'm...

Hi all! I have data that include 20 samples divided into 2 groups (category A and category B). The groups are independent, none of the value in one group repeat in other. N(A) =14, N(B) = 6. here is the data: category A category B 0.0119888167559 0.023185483871...

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Hi all, I need some help with some statistical work: So, I am trying to understand how I can transform time into probability. I have 2 teams playing a game for 10 minutes. One team scores 1 pt per each minute and the other team takes 1,5 minutes in average to score one point. I want...

Hi, I have 10,000 data points referring to data on dogs that follow a positively skewed distribution that I have grouped into quartiles. I would a second distribution (highly correlated with the first distribution) associated with the same set of dogs whereby the distribution represents a...

Hey everyone, I'm doing some equivalency testing with both the CI approach and TOST to demostrate the equivalency of two scanning methods. For most of my samples, results align as one would expect, i.e. if the CI lies within the upper and lower bounds, the p-values calculated with two...

down vote favorite I am comparing maths and chemistry scores of students in several schools. I am not comparing the schools with each other. I am just trying to say that students do better in maths than in chemistry in all of the schools studied. So I am comparing the maths and chemistry...

Hi There I've goodness of fit my data 2 times. one time for normal distribution and another time for T.distribution. I have about 2500 data and I need to do graphical illustration now. my graphical illustration should be mix of ecdf and cdf for each of them( normal and student t). I'm pretty...

Hi all, I'm generating a random normal distribution and i don't control the mu and sigma (its a matlab function that i need to use because the ratio between the numbers). Is there any way to change the mu and sigma and still keep the same ratio between the numbers in the vector? I hope you...

For the Normal Distribution, why is the case that "<" (less than) is the same thing as "<=" (less than or equal to), computationally? That is, why can we summarily disregard the "equality" portion?

I want to develop my own Normal Distribution calculator, to provide to a developer to perform a task within an app. I want a user with little knowledge of statistics to be able to perform, and understand Normal Distribution calculations. Here is what I want it to accomplish . . . Given the...

Suppose that in an apartment building run by the Probandstat rental company, the inhabitants's weights follow a normal distribution with mean 73.0 kilos and standard deviation 13.65 kilos. A new elevator must be installed. The elevator company rates the safe carrying capacity of the new...

The minimum force required to break a particular type of cable is normally distributed with mean 12,432 and standard deviation 25. A random sample of 400 cables of this type is selected. Calculate the probability that at least 349 of the selected cables will not break under a force of 12,400...

Dear folks, I am interested in statistics but I never had a course in college and I've had to learn a few basic things myself. This time, I am working on something that is beyond my comprehension. I have a set of environmental data (20 soil samples) which I am playing around with. (See below.)...

So I'm currently analyzing several sets of data, that all represent the exact same type of data. There are multiple sets of this data, but however are in different forms. That is, some of this data is in the binary form, either presence of absence, while others are in the quantitative form. My...

Hi There, I would like to know more about transforming data. I know that for parametric statistics data needs to be normally distributed, but I am confused about when this does and does not apply. Doesn't transforming data to make it normally distributed hide any experimental effects you...

Hi there :wave: So I haven't a clue where to start and am hoping someone on here can point me in the right direction. I'm starting to analyse my data from laboratory research but I don't know which test to use. My data is numerical and follows a normal distribution. I have 2 different...

Hello everyone, new here, glad to be here! I have what might be an unorthodox question. I use the matlab function 'mnrfit' http://www.mathworks.com/help/stats/mnrfit.html to compute a logistic regression model given input data. The matlab function 'mnrval' performs the inverse...

Hi all, Please forgive the slightly long winded explanation, I could really do with some help here. I have a computer simulation which contains multiple variables to which I have applied random perturbations in order to simulate the possible error. The random perturbations are in the form...