# Tagged Questions

Descriptive statistics summarize features of a sample, such as mean and standard deviations, median and quartiles, the maximum and minimum. With multiple variables, may include correlations and crosstabs. Can include visual displays - boxplots, histograms, scatterplots and so on.

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### Difference between descriptive and predictive modelling

I was wondering if anyone could help me clear up the difference between descriptive and predictive modelling. I am trying to build a model to predict where house prices will go up. To do this I need ...
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### Which statistical test to use to determine if some values Ys influence X?

I have a NetLogo simulation which has a parameter to determine how to calculate some distance. This parameter can take one of three values for each simulation run. The experiment consists of running ...
16 views

### using variance for dimensionality reduction [on hold]

I have a dataset of 23 variables and 1 class label data. Suppose my variables are (A,B,C,D,E......) Now when i calculate the variance, there are some variables which have very low values.. which state ...
46 views

### Is this a skewed distirbution or bimodal?

It appears that this distribution may be right skewed and bimodal. Or is it just right skewed only?
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### help on mixed models in spss

I am trying to analyze a complex data set and I got confused. Here is a brief explanation: Everyone has different beliefs, i.e., fate, luck, etc. I identified 5 belief types which I measure with some ...
17 views

### calculating weighted CIs and interpretation

I have a weighted mean and I would like to calculate a weighted confidence interval and had a couple questions about interpretation. If one calculates the standard error of the weighted mean ...
51 views

### Interpret box plot when no mean is shown

I am trying to understand what is shown in the following boxplot given the information from the Wikipedia article on the box plot. The problem is that we see no mean, and only whiskers in one ...
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### Which ANOVA model should I use?

I have a data set containing root, shoot, and seedling growth measurements from 5 treatment groups (at different concentrations, 3 replicates) including control. There were no separate control groups ...
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### Predicting continuous position using input variables of unknown quality

The problem I'd like to solve can be reformulated as follows. Let's consider that I have to go to some parties and I would like to find out where in the room I am most likely to have a good time. I ...
35 views

### Is forecasting and predictions part of Inferential or Descriptive?

Can someone please explain to me which statistics forecasting and predictions are part of? Inferential or Descriptive? I am working on an homework. I was unable to come across the answer in my reading....
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### Outlier/Anomaly detection in strings

Can anyone suggest methods/techniques to find anomaly in string data from database. The data contains road names, so every cell is unique. By outlier, I mean the strings with weird stuff(special ...
33 views

### Figuring out which delta to use when calculating standard deviation

So I'm working on something for work where I'm trying to refine how we do our financial projections and one of the key components of that is determining monthly unit sales, specifically, what we're ...
17 views

### statistics on Cross Validated posts [migrated]

since CV is about statistics and machine learning, and this forum has been gaining popularity, can the organizers please share some statistics about CV. I'm sure a lot of folks would be interested in ...
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### In a R markdown statistical analysis report, is it appropriate to encapsulate trivial functionality?

When preparing a report for a complex statistical analysis using R markdown, is it okay to encapsulate minor functionality so major functionality stands out more? Could hiding trivial details cause ...
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### How to find standard deviation/error of average cumulative values?

I am a science student, however unfortunately a complete newbie in math and statistics. I am measuring soil respiration for my master thesis project and have a certain amount of carbon respired that I ...
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### Percentile of a data set with more than one variable

I have a data set with more than two variables 1.Number of transactions 2.Money Deposited Now I want to find the 95 percentile of people based on the information.I understand that taking quantiles is ...
2k views

### What can one conclude about the data when arithmetic mean is very close to geometric mean?

Is there anything significant about a geometric mean and arithmetic mean that fall very close to one another, say ~0.1%? What conjectures can be made about such a data set? I've been working on ...
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### Can I run statistical tests on descriptive statistics like mean and standard deviation? (i.e. no raw data)

I'm trying to figure out which statistical test to run on my data, but it has been processed so that now I have gathered the mean and standard deviation values to be used instead of the raw data. I ...
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### What is the most effective way to get a baseline rating prediction from netflix rating data?

I am doing an assignment where I am working with some of the Netflix Challenge data. I have a database that maps movie ids to customer ratings of that movie and a database of customers mapped to ...
55 views

### Which of the several measures of d-statistics is better for a meta-analysis of effect-sizes?

Several measures including Cohen's d are available for computing d-statistics. It is difficult to choose one of them for a meta-analysis? Are there any guidelines ?
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### How to measure the impact of a product on the global revenue?

We have products daily revenue and when each product started being sold by the company. We also have different break-down of product revenue by location, store, sales person, etc. We need to measure ...
18 views

### Why confidence interval is important when point estimator is close to zero? [duplicate]

When the point estimator is relatively small numbers, a confidence interval is likely to contain zero, be fairly wide and include both positive and negative values. Basically, when CI contains zero ...
18 views

### What is the relationship between median disease free survival and median follow-up distribution?

I created a Kaplain Meier disease free survival curve with the following statistics (in months): ...
52 views

### Intuition behind pearson correlation, co-variance and cosine similarity

In this post, the best answer gives excellent mathmetical explanation among pearson correlation, co-variance and cosine similarity. Where I quote here ($\mathbf A$ is the data matrix). If you ...
28 views

### probability of a single value belonging to a population

what is the appropriate approach to estimate the probability of a single sample belonging to a population? Specifically, I am calculating a particular value from the comparison of two time series. ...
20 views

### How can I calculate the average age of survey respondents? [duplicate]

A question in my survey asks about the age of respondents. Respondents are asked to choose one of these four ranges: 18-29 30-49 50-64 65 and over How can I calculate the average age of respondents?
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### How to standarise percent values 0 - 100%

I'm working on dataset that contains a variable from 0 to 1 (0 - 100%). Distribution of the variable differs depending on the context (defined by another variable). Depending on the context the ...
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### What are some of the more popular variable transformations and why/when are they used (to handle what types of distribution problems)?

Like the title states, I'm interested in learning about the more popular data transformation techniques. I know the internet is abound in this information, but I'd like to hear from those working ...
13 views

### usage of adjbox() in R [duplicate]

Anyone here who could describe the usage of adjbox()? Is it used for very skewed distributions to have a more generous range like the boxplot? What is the formula like mean+1.5*IQR in boxplots? Is it ...
14 views

### chisquare outlier test assumptions

what are the assumptions of the chisquare outlier test? ( in R: chisq.out.test()) Is it only applicable if the data follow a certain Distribution? What is the idea of ist Definition of outliers? ...
17 views

### level of variable?

I was looking at this What does the level of a variable mean? I can only think of categorical variables with 2 values, like gender. Is there continuous variables with only 2 levels?
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### Appropriate testing for outliers [on hold]

I want to perform an outlier-test for my data. The distribution of the data looks like a hyperbola (there are many values near 0, all values are >0). Sample size of data is 5000. I want to find an ...
12 views

### PDF from standard deviations plot

I must consider a plot like this that shows the bounds on $x$ (in this case $\sin^2\theta_{12}$), in terms of standard deviations $N\sigma$ from the best fit. How can I extract the PDF of the $x$ ...
16 views

### statistical tolerance

My request is: I have data (sums of money) and someone calculated tolerance limits for the data. I want to validate these tolerance limits with statistical methods/arguments. Does anyone know ...
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### Responses to likert scale - how do I work out if the same participants are saying don't know

I have a 10 questions whose responses are on the likert scale (agree, neither agree nor disagree, disagree, and don't know). I want to work out whether those that selected 'don't know' across all the ...
7 views

### to constrain a parameter estimate to obtain unique estimates in R LAVAAN for CFA

I need urgent help, I need the script or command to constrain a parameter estimate to obtain unique estimates in R LAVAAN for CFA. Like If Social Influence got 4 items in a model and I want to put a ...
34 views

### Are the distances of the kNN i.i.d?

Imagine the set of i.i.d observations $D = \{x_i\}_{i=1}^N \subset X^n$. Let the distance function $d \colon X^n \times X^n \rightarrow \mathbb{R}$ be used to find the $k$ nearest neighbors to the ...
14 views

### Finding Power Function for a LRT test

I am trying to solve the following problem: Let $X_1, . . . , X_n$ be a random sample from the $Uniform(θ, θ + 1)$ distribution. Derive the power function for the LRT for \$H_0 : θ = θ_0\ vs.\ ...
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### Best metric for differences between shares

I am looking for a simple metric to measure the differences in expenditure shares on commodities which were calculated differently. Thus, there are two scenarios, both of which report expenditure ...
15 views

### Unsure about what statistical test to carry out

I have a blood count data with a sample size of over 3000. I am dealing with these variables only: age, sex and WBC:Platelet(ratio). I am using SPSS and already done some descriptive statistical ...
31 views

### How to detect the inflection point or the change point in a Q-Q plot?

Following are two QQplot. Both of them has an inflection point, which can be found easily by human eyes. However, I'm not sure whether there is a robust statistics way to find it.. Does anyone have ...
50 views

### How to properly display changes in percentages over time?

Our company is developing self-learning software that extracts data from documents and enters it automatically into text-fields in some other software, on behalf of the user. These suggestions aren't ...
17 views

### what method to test percentage against population percentage?

I have population of 6 regions, and also customers from these regions. What is the best way to test if the percentages of customers from these regions are about the same as the population percentages?...
144 views

### How to extract distribution information from descriptive statistics?

In my thesis, I am trying to perform a Monte Carlo simulation with a set of parameters, where I take a random value from a known distribution to calculate a singe run of the simulation. However, for ...
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### What is the difference between doing a linear regression and exhaustive descriptive statistics?

I'm doing a report of the differences between women and men in their performance on a test with variables like: age, education, race and of course genre. I have two options: doing a linear ...
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### Why run a post hoc wilcoxon signed rank test after Friedman test, why not just skip to Wilcoxon sign test instead?

I understand that one is required to run post hoc tests after the Friedman test. For example, while the Friedman test may find a statistically significant change amongst 3 treatments, one may follow ...
35 views

### Does descriptive research have dependent varibles?

I am doing a research proposal for a descriptive study to identify the health beliefs and perceptions among women to mammography breast cancer screening. I am using a Likert scale that is divided into ...
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### Can I obtain the means for two groups using their mean difference?

I have a study which provides the mean difference for two groups (alongside 95%CI, SE, n and p-value). I would like to extrapolate the raw means to use in Revman to perform a random-effect SMD meta-...