Questions tagged [z-statistic]
The statistic used in z-test, namely the ratio of a parameter estimate and its estimated standard error.
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Correlation and $z$-Transformation for Vectors With Correlation Structure
Consider a set of $p$ pairs $(x_1,y_1),...,(x_p,y_p)$, the sample correlation coefficient is
$$r=\frac{\sum_{i=1}^p (x_i-\bar{x})(y_i-\bar{y})}{\sqrt{\sum_{i=1}^p (x_i-\bar{x})^2} \sqrt{\sum_{i=1}^p (...
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Source for Test if Two Populations have Different Defect Rates
I have two populations of items and I want to test if the defect rate between them is statistically difference. I have a sample from both populations of different sizes and I know the number of ...
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Benjamini Hochberg Procedure [closed]
I am working on a problem for class related to multiple testing where I would like to run the BH procedure with a known $\pi_{0}$, denoting the proportion of hypothesis that are truly null, given ...
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Calculation of standard deviation of the mean changes from the p-value or z-value of the Wilcoxon test
I am conducting a meta-analysis of observational studies without a control group that compared a parameter's value before and after an operation. All included studies have reported their results as ...
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Is there a z transformation for the correlation of non-normal distributions?
I'm writing code to calculate if the correlation between two random variables is significant.
I've recently come across Fisher's z transformation as a method for finding significance. But from reading ...
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Is a Z value of -4.703 statistically signficant? [closed]
I was wondering, i have a Z value of -4.7 is this a significant positive skew based on a 1.96 cut off?
And for Z value of Kurtosis of -0.16 is this proving its non significant as its less than the 1....
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Confidence Interval - small dataset (30 records)
I'm trying to calculate a confidence interval for data analyst salary population. I have a very small dataset from a job posting site that contains only 30 records. The dataset doesn't follow normal ...
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Calculate probability of minimum number of sample types within a sample distribution - z-statistics vs. binomial distribution
(The title may have to be changed, because I am learning statistics and can't describe problems through the use of the correct terminologies yet)
I have the following question:
"90% of all plant ...
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In standard normal distribution table how I deal with value of Z greater than or equal to 5
How can I deal with sample distribution table when Z is greater or equal to 5?
For example:(-2.04 <z<-5.96)
Sample distribution table value for -2.04 will be 0.2018 then what will be the sample ...
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Using random intercepts or z-standardizing within factors: Two identical ways to account for variance between factors?
I have the following (simple?) question about statistics: I have a dataset where I look for correlations between variables and would like to control for differences between factor levels. For ...
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Is this formula for percentile from z-score correct?
Preface: I am not a mathematician. I have a basic understanding of statistics but am not familiar with mathematical notation beyond high school algebra.
I am a software developer maintaining medical ...
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critical Z-statistic vs sample Z-statistic
A hypothesis that the population mean is less or equal to $x$ should be rejected when the critical Z-statistic is greater than the sample Z-statistic. $x$ is any number.
If $x=5$, the statement is ...
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Comparing n population proportions
In the examples I am reading (which includes Stats for Dummies!!) most examples of null hypothesis testing reference 2 populations. However lets say I complete a survey and get the following results:
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Should we always calculate the z in a confidence interval as 1 - (alpha/2)?
I'm currently beginning my studies in statistics and all of the examples of confidence interval questions I studied used (let's assume a 95% confidence interval) as a z formula ...
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This function can get p-value from which statistics?
I know that I can get p-value from z-statistic (called zval here) using following function (Python):
pval = 2*(scipy.stats.norm.sf(abs(zval)))
or with:
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