# z-test's questions - English 1answer

185 z-test questions.

### 2 sample Z test for non normally distributed data

1 answers, 23 views hypothesis-testing z-test
I'm trying to analyse the impact of a marketing campaign and I'm looking to identify the most appropriate statistical test. I have one group of customers who received the campaign (approx 100,000 ...

### 1 One-Sample Test for differences between questionnaire-answers

1 answers, 19 views hypothesis-testing proportion z-test
For a rather large sample (>800 participants) I have answers from a questionnaire, containing multiple Yes/No-Questions. What I want to find out is, if the proportions of yes & no's differ ...

### How to determine if a variance of population is known in a A/B test?

0 answers, 22 views probability distributions t-test z-test
Our website is a e-commerce platform for user to view and purchase Fashion items. We are going to launch multiple A/B tests to check if the changes in UI could improve the number of views and ...

### Comparing Means: Multiple Dependent Variables

1 answers, 1.006 views t-test manova z-test
I am using school-level data to compare mean scores for two groups (Group A schools and Group B schools), as measured by a series of indicators: 1) grade-level exam percentile, 2) percent of male ...

### 1 Standard normal intuitive understanding

3 answers, 51 views normal-distribution terminology z-test
What does it mean for a standard normal to have mean 0 and standard deviation 1? I'm having trouble understanding - what is a "normal variable"?

### What is the Appropriate Test to Compare Pearson's Correlation Coefficient?

Let say I have this simplified data set which contains four variables (2 categorical, and 2 numerical types): ...

### 1 Normality assumption for t/z tests

I have what is probably a silly question regarding normality assumptions for t/Z tests. As I understand, t/z tests require that sample data was obtained from populations following a normal ...

### Find if two groups are different where one is a subset of the other

1 answers, 17 views chi-squared z-test
I have a dataset of 3,500,000 categorical observations that can be grouped by an ID. In these categories u occurs 25,000 times. How can I test to determine if a ...

### P-value and confidence interval in MVT testing

Context: website A/B testing When calculating P-value and confidence intervals for each variation in an experiment with more than 2 variations (control, variation 1, variation 2 ...) should there be ...

### -1 chi2 + z-test not yielding the same results?

1 answers, 35 views contingency-tables z-test
With a 2x2 contingency table, I believe a chi2 test should be equivalent to a z-test -- from Wikipedia: "Two-by-two contingency tables: When the test is applied to a contingency table containing two ...

### 1 Using a general linear model to perform z-test

I am trying to perform a z-test with a brain-imaging software. I was told that the best way was to use a general linear model with one subject in one group and the rest in the other group. Using this ...

### methodology to analyze differences between groups

0 answers, 17 views proportion z-test
My dataset (n=2,000) shows total daily sales and I can plot a trend and show via a s-test that the average number sales is different in 2016 vs 2017. I also have the information in the data indicating ...

### What hypothesis test should I use to compare the overall performance of two different athletes in a 100m race?

1 answers, 15 views t-test chi-squared z-test
I am sourcing data from IAAF's website to test my hypothesis - Athlete A is a better athlete than Athlete B (comparing their times in the Olympics). Since I would be sourcing the data from IAAF's ...

### 2 two samples, hypothesis test of proportions t or z test

1 answers, 822 views t-test proportion z-test
I have two samples of documents where one sample contains documents of a certain category and another sample contains documents of another category. I am analysing the occurrence of a certain word in ...

### What would be appropriate test to compare two lists of dichotomous variables?

Colleagues, can't wrap my mind on simple question, please help! I have two products and list of their attributes. My respondents make an answer which product on each attribute they prefer. Finally ...

### Should I be using Z-tests or T-Tests for my scientific data?

0 answers, 38 views hypothesis-testing t-test z-test
I've conducted a survey for my thesis where I ask a series of questions of the format:A statement relating to the experimentThen the participants answer ...

### 1 Comparing distribution of sample proportions to population proportion

I'm trying to find out whether there is a statistical method for comparing a distribution of sample proportions to a distribution of population proportions. For example if I have only two groups, A ...

### 5 z-test for one population proportion hypothesis with a small sample size

1 answers, 450 views t-test small-sample z-test exact-test
I have asked a "yes/no" question to a small group of people (n = 22). From the 22, 14 answered "yes" and 8 answered "no". I'd like to find out, with 90% confidence, if the majority of my population (> ...

### Which statistical test should I use (comparing two cohorts)?

So I am doing some research in the field of Medical Physics, in particular radiation treatment with photons and protons. Now, I have two cases I am unsure about. 1) Here I have several patients. ...

### algorithm for testing a variable

I want to test if a quantitative variable is different in 2 groups. As for what I understood so far, here is the algorithm I should use : if the length of my 2 subgroups are >30 --> z-test else, ...