Stack Exchange Network

Stack Exchange network consists of 175 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

Questions tagged [descriptive-statistics]

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.

0
votes
0answers
23 views

Want or don't want data analysis [on hold]

If we have data for specific products and the results of questionnaires if they want this produce or not, something like this one: ...
0
votes
0answers
5 views

How to view the descriptive statistics of two between subjects variables in SPSS? [on hold]

Let me first explain the design of my experiment. I have a mixed factorial design. So the participants are first divided into two groups(NATURE and URBAN). The participants also perform a perception ...
4
votes
1answer
37 views

Can you statistically compare one subset of a population with the whole population?

I have data (total $n=90$) from a district of testing scores from $3$ subsequent years. I would like to compare MY school to the other schools, but I do not know which schools the other participants ...
2
votes
1answer
14 views

What interesting data manipulations can be done over 70x5 data points in a school context?

TL;DR: I am looking for ideas for a school assignment in basic statistics. Context: My son (14 years old, French class 3ème, equivalent to 9th grade) got a group assignment in Mathematics. They ...
0
votes
1answer
20 views

Statistic to measure no.of cancelled members

These percentages indicate how many male vs female members cancelled a subscription we offer. Male Female 22% 13% Looking at the ...
0
votes
1answer
12 views

Is attempting to discern gender discrimination in a distribution descriptive or inferential?

Let's say I have a given sample population $P$, that describes the traits of a group of people as a predictor variable, and whether or not they are CEOs as a response variable. I am trying to ...
0
votes
0answers
5 views

Summary statitics to describe topic x term distribution in NLP

I created a topic model which outputted 11 topics out of 437 terms on ~60000 small documents. I wanted to show how good each topic is. But I don't know what "good" means in this case. Here's the ...
0
votes
0answers
18 views

How to do random simulations on R [closed]

Draw 1000 Uniform random variable. You know the true mean. You can use the standard deviation of your data or you can calculate the true standard deviation and use that. How often does your data fall ...
0
votes
0answers
22 views

Sub-group's contribution to a group's mean

I have a statistics 101 question, which I hope the community can help me with. Is there a statistic that summarises a sub-group's contribution to a group's mean? For example, given the following data: ...
0
votes
1answer
11 views

Best Way to Aggregate further and Analyze a Data Point that is Already an Average

I want to understand how much time (on average) each Customer Service Agent (CSA) is taking to reply to messages that are sent by a Customer on a single chat. E.g., "Charles took on average, 22s to ...
0
votes
0answers
16 views

Computing a p-value using the ratios of the means and ratios of the variances

When you have a ratio of the means ($\mu_1/\mu_2$) and ratio of the variances ($\sigma^2_1/\sigma^2_2$) from two distributions, how can you compute the p-value telling you whether the means of the two ...
0
votes
0answers
15 views

Determine Sample Size [on hold]

In determining sample size, how to analyze this problem. You plan to sample students from each of the following strata: Sophomores, N=1000; junior=N=500; Seniors, N=300. Answer the question below. ...
3
votes
0answers
21 views

Measures of central tendency for right-skewed size distributions

Suppose we are looking at a right-skewed size distribution such as the distributions of income, casualty losses, or flood sizes, and we want to look at some alternative measures to jointly represent ...
3
votes
1answer
51 views

What's a good measure of spread when using a weighted average

It's often useful to display a measure of spread when presenting an average. Example: the average revenue per customer per transaction is \$100, meaning that (assuming a distribution roughly ...
0
votes
0answers
25 views

Comparing populations with multiple variables

My datasets represent the sales of a company with the phone calls they made to promote the products (some zones have sales but no phone calls). I also have the total population per zone which I Can ...
2
votes
2answers
73 views

Calculate E[X] from incomplete data?

The exercise I'm doing describes the random variable $X$ as the following ...
6
votes
2answers
194 views

How to detect and quantify a structural break in time-series (R)

Background So first some background to gauge the level of understanding I might have. Currently completing MSc thesis, statistics has been a negligible part of this although I do have a basic ...
0
votes
1answer
32 views

Summary statistic of variance across measurements with different units

I'm looking to calculate a metric that summarizes variance for multiple characters among repeated observations for different groups. Say you measure height, width, and weight among four different ...
0
votes
0answers
9 views

% variation on 1/x function

My data (X) is the rank position of units sales (y). Eg. x=1 top seller, x=1000 is the 1000th top seller I know that sales number can be estimated by: units(x) = $N_0x^{(-0.5)}$ Now I would ...
0
votes
3answers
80 views

can I work out *the* standard deviation from a value given as “+/- 1 standard deviation”

I'm confronted by a table of values: 17.1 (16.6) 18.0 (9.5) 38.1 (22.5) 30.6 (16.7) In the left-hand column we have some mean values. I’m told that the values ...
1
vote
1answer
30 views

Estimating probabilities from truncated set of counts?

If I have a truncated histogram like this, where the ordinate is the number of occurrences $N_X$ of each value of $X$, and the abscissa is the value of $X$, is there a way to estimate the probability $...
0
votes
0answers
9 views

Can a difference between statistical deviations be interpreted as a statistical deviation?

I have a cross-table of three variables (2x2x3 design) and I obtained 7 outcome variables for each condition. Since each condition is not a group of participants but a group of models sample size is ...
0
votes
1answer
30 views

Constant Variance Assumption in Linear Regression

It seems to me that the following plot of "Residuals Vs. Fitted Values" violates the assumption of constant variance, since for lower fitted values, there are fewer points whereas for higher fitted ...
0
votes
0answers
19 views

How to define a measure of dispersion of a group of points in a given area?

I'm working in a simple exercise in my current trining to data analyst. I need to define a measure (indicator) of how good or bad its an area according with two variables. The first variable is the ...
2
votes
1answer
26 views

Central Tendency for Negatively Skewed Data

I am trying to understand how to best describe left or negatively skewed data in terms of central tendency. I have provided code below that simulates such a distribution, as well as the source code ...
2
votes
0answers
29 views

Need help choosing appropriate weighted average (noble cause)

We are lobbying our council to open a primary school in our area, and I'm trying to demonstrate the need. I have location information for all houses and schools in the county, I can calculate ...
2
votes
1answer
29 views

User-Specific Activity Level Along Weeks

I am assigning Low | Medium | High activity levels to users once a week. At the end of an entire period,a user has been assign n weekly activity levels among {Low, Medium, High}. Let k be the total ...
1
vote
0answers
24 views

How can I find required sample size to meet certain condition in R?

I need to find the required sample size to meet certain condition in R. The question where I need help is posted below. Suppose a forester would like the sample mean to be within 1 square inch of the ...
1
vote
3answers
50 views

what statistics should I use for demonstrating two data points

I want to plot a time-series of emissions of a pollutant. For each year, I only have two data, one min value and one max value for the emissions. I only demonstrated the min, max and mean value in ...
0
votes
0answers
16 views

How to determine the distribution a dataset follows without plotting or visualizing it?

I am given a data set of 100k instances and I am being told that it belongs to one of four statistical distributions (normal, truncated normal, poisson and uniform). I am wondering how I may go about ...
1
vote
0answers
12 views

What assumptions about the data are require for Multiple Correspondence Analysis?

In multiple correspondence analysis, what assumptions about the data are necessary in order to find the principal coordinates for the rows and columns?
0
votes
1answer
32 views

Calculating an overall standard error/confidence interval across multiple datasets

I am using five different datasets (with 250,000+ samples in each) to calculate an overall average across them. I also would like to calculate an overall standard error/confidence interval for them. ...
0
votes
0answers
35 views

R: Chi-squared comparing one reference group to two other groups

If this question has been answered elsewhere, please direct me to the appropriate post. thank you! Below is an example of part of my data. I am trying to determine if there is a statistically ...
1
vote
2answers
46 views

Interpreting percentage of an outlier in a box plot

I have a dataset of 21 points. Below is a box plot of that data. I am trying to interpret this boxplot. Is it safe to say that 96% of my data points fall under 48? I derived 96% by dividing 100 with ...
0
votes
1answer
11 views

index and base year

I am creating a league table of a group of people with the aim to track their performance on 5 KPIs using indices. Base month value is set to 100. Out of 5 KPIs, an increase in 3 indices means good ...
0
votes
0answers
11 views

Large datasets, deviations and noise/signal

The below excerpt mentions that 'large deviations' are more attributable to variance than to information. What does the author mean when he says 'deviations'? Deviations from what? And why would it be ...
0
votes
0answers
18 views

What is local stationarity and how to detect it in time series

What is local stationarity time series and how to detect? and what is the difference between it and between global stationarity?
0
votes
2answers
20 views

A four way categorical variable with a frequency, what is the best solution? Chi-square or something else?

We are doing research to see if images quality affects engagement. We are doing this for 3 products. We are doing this for 4 image quality levels. And for each of them we are checking the engagement ...
0
votes
0answers
27 views

Can a Z-Test of Two Sample means in Excel be used to answer two separate hypotheses

Can a Z-Test of Two Sample means in Excel be used to answer two separate hypotheses. 1) Hypothesized Mean Difference=0 (Two-Tailed) (NULL vs Alternate, ho = ha) 2) Treatment > Control (One-Tailed) ...
0
votes
0answers
30 views

Comparing a distributions between large datasets

I have $2 < n < 10$ algorithms that I have applied to $10 < n < 500$ time series with ten different variables. The job of the algorithms is to produce a result that is as close as possible ...
0
votes
1answer
22 views

The best (or most conventionally acceptable) way to describe under-representation of a group in a sub-population

Suppose that 50% of the population at large are women, but in a certain field, only 20% of the professionals are women. Suppose further that I want to write a bullet point that reads: ...
2
votes
0answers
50 views

Descriptive statistics (frequencies, counts, proportions) after multiple imputation

I recently ran a multiple imputation using the mice package in R to generated imputed datasets. I have no problems with running inferential statistics on the pooled data (logistic and Cox regressions) ...
0
votes
0answers
4 views

Can Mplus run invariance testing if you only have access to summary data

Does anyone know if you can run invariance testing if you only have access to summary data. I have one data-set with full item level information and can only access summary data on another data-set (...
0
votes
0answers
6 views

Understanding percentile computation [duplicate]

I understand percentile in the context of test scores with many examples (eg. you SAT score falls in the 99th percentile), but I am not sure I understand percentile in the following context and what ...
0
votes
0answers
13 views

Understanding lift curves

I understand the the cumulative gains chart shows the percentage of found targets (y-axis) (so the sensitivity) against the number of tested observations (x-axis). For the lift chart it seems that ...
1
vote
1answer
28 views

How to establish the effects of a competitor near my store location?

As part of my studies of statistics, market analysis and data analysis, I’m facing the following problem but not sure if the answer I’m proposing it is correct or not. A commercial retail store with “...
0
votes
0answers
16 views

Hypothesis statement for Factorial design

I have a factorial design with two independent variables A and B. The factor A has 2 levels and factor B has 5 levels. Now I want to see their main effect and interactive effects on X. I am not sure ...
6
votes
3answers
145 views

Fit data to parametric distribution

I have data with nice bell-shaped histogram PDF. However, the Normal distribution fitting (by calculating mean and variance) does not work as the figure below. My question is that if there are other ...
6
votes
2answers
516 views

Can two different distributions have the same value of mean, variance, skewness, and kurtosis?

Assuming that you have two discrete population distributions. Can they have identical values of mean ,variance, skewness and kurtosis while being different in shape visually ? Do these four values ...
1
vote
0answers
24 views

Calculating CI's using bootstrapping on the holdout test dataset

I’m trying to calculate 95% confidence intervals for the sensitivity and specificity of a decision model that I’m building. I’ve split my dataset into 90/10 train and test sets. I’ve used the 90% ...