# Questions tagged [z-score]

The z-score of an observation is the number of standard deviations above or below the mean of the distribution of observations from which it came.

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### Is there a maximum limit for z-score? [duplicate]

I am comparing gene expressions between tumors (n = 44) and normal samples (n = 32) and trying to visualize them through a heatmap. I converted the expressions into z-scores using ...
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### Obtaining z-scores for coefficients of quantile regression with sampling weights applied in R

I would need to obtain z-scores for coefficients of quantile regression with sampling weights applied in R to be able to compare results from different datasets. Can I just compute them as "z-...
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1 vote
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### to determine the appropriate threshold of the z-score for the non-normally distributed data

I am interested in CPI. And I need to identify outliers in the series. For that, my instructor mentioned about the number of standard deviations from the mean that a data point is. This is Z-score. I ...
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### How to deal with replicates and z-scores?

How would you deal with replicates if you want to calculate z-scores? My ultimate goal is to make a heat map of gene expression. To do so I have to calculate z-scores. The analysis consisted of some ...
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1 vote
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### Z-scores (heatmap) and statistics with replicates and outliers

My group performed a biological assay.The assay was performed for 6 different cell culture conditions (columns) and for 6 genes (rows). However, it was also performed 5 times (5 replicates) per each ...
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### Normalization of time-series data before computing Dynamic Time Warping (DTW)

I am interested in a proper normalization method of my time-series data before computing the dynamic time warping (DTW) distance. Situation: I have four time series (colored in two different green ...
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### Better method to adjust Z-score

I came across a question a few days back in an interview that, in a time series of something, let's say price, if there's a jump either side, the z-score immediately doesn't change or it stays ...
39 views

### 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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1 vote
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### Combining Z scores of Correlated Test Results

I have the Z scores of a population of N for M different tests, where N is O(10000) and M is ~50. The results of these test are not independent, but we can produce a reasonable estimate of the ...
1 vote
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### Confidence interval for a normal RV that its std is the mean of a different normal RV

Question: Suppose $X\sim\mathcal{N}(\mu_X,a),Y\sim\mathcal{N}(\mu_Y,b\cdot\mu_X)$ where $a$ and $b$ are known, but $\mu_X$ and $\mu_Y$ are not. What confidence bounds can we give for $\mu_Y$ from one ...
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1 vote
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### What does sensitivity refer to in this study?

A study I'm reading is looking at some metrics (number of peaks per meter, etc.) to compare them on a young and elderly group of subjects. It states 'Sensitivity and within-group variability were ...
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### regression wtith t scores

I have performed a study in which I converted performance on a cognitive test to z statistics and from that derived t scores. We would like to examine the relationship between t-scores and various ...
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### How many z-scores should be used when determining a p-value?

Suppose one wants to test whether the average sum of tickets in a box is X. Since the z-score is computed by sampling N tickets and then seeing how many SE's away the average is from the expected ...
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### Distribution of a quantity similar to the $t$ statistic

Suppose I have samples $A$ and $B$ from $N(\mu,\sigma^2)$ with unknown mean and variance. The sample sizes are $n_A$ and $n_B$. I construct two statistics: $$t_A=\frac{\bar X_A-\mu}{s_A/\sqrt{n_A}}$$ ...
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### How can I add the z-score and its confidence interval from an estimate using emmeans?

I'm trying to add to the following model the z-score value and its confidence interval after using the emmeans package. The model: ...
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### Proportion C.I confidence level with a change of variance

I recently learned about confidence interval for proportion now let's say i use a Z score and get the confidence interval of 95% as follows: $$C.I = \hat{p} \pm Z_{(1-0.95)/2} \sqrt{p(1-p)/n}$$ now ...
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### Preferred typography for "z score"

I would like to know if there is a preferred typographic form for the term "z score". A search on Google scholar for "z score" shows six forms no markup: z score hyphenated: z-...
1 vote
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### How should I calculate z-score? Two groups with repeated measurements [closed]

In my experimental design I have two groups, Control and Experimental, both with Pretest and Posttest measurements. I want to calculate the zscore to be able to generate a composite zscore from ...
1 vote
33 views

### Different scales in psychological testing -- z score or other standardization ? within anova using repetead measures

I'm pretty sure this is a basic statistics question; however, here it goes: In psychological testing, let's assume some participants were tested with three different tests. The first goes from 1 to 10,...
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### Versatility and validity of aggregate algorithm for a multiple criteria decision problem (averaging)

I'm trying to aggregate different variables in multiple scales and distributions. The distributions are not known beforehand, but I want to generate a general statistical value that represents all the ...
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### Computing Z scores AP Psych

My report is looking at the effect of belief in conspiracy theories and critical thinking abilities, on engagement in politics. I've basically got to do a factorial ANOVA and my IV's are: Conspiracy ...
1 vote
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### Z score comparison in longitudinal studies

I have a longitudinal study with two time points (before/after), whereas a particular score was standardized across all individuals and time points, and thus provided only in terms of z-scores. (Edit: ...
99 views

### Confidence interval for the ratio

I have a problem that each customer gives us a revenue and a cost, one of the indicators of the company is the: $\frac{\sum Costs}{\sum Revenue}$ To estimate the confidence interval for this parameter ...
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### Relationship between z-score and the normal distribution [duplicate]

I am confusing about the relationship between z-score and the normal distribution. Do we apply z-score normalization to get a data with normal distribution, or given we have a normal distribution, we ...
535 views

### How to choose the Normalization method for a co-occurence matrix?

I have a co-occurrence matrix about hashtags usage (The value in the cell means the number of times two hashtags appear together in a single tweet), it is transformed from a 2-mode matrix. Now I want ...
1 vote
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### Rolling z-score or z-score? [closed]

Suppose that we have some time series data, in what context we use rolling z-score and when do we use z-score?
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### How can I evaluate a group of Z-Scores?

I have some elements in a dataframe, and for each one of them I have a z-score for some parameters that describe them. If I wanted to "sum up" all the Z-scores into one value in order to ...
1 vote
92 views

### When can we use the z-score? (Since it's impossible to know the population SD)

Sometimes I see papers that report the z-score. I am confused because the z-score requires us to know the population standard deviation, which is impossible. What are some reasons people still report ...
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