A brief numerical description of a set of data.
0
votes
0answers
20 views
Pre and post test measurements and evaluation
I am implementing a diabetes prevention program. How would I measure changes in individual: weights, BMI, Lab values? How would I evaluate them to ensure validity and reliability?
0
votes
0answers
26 views
Sampling for quality control
I would like to do some quality control study for a set of manufactured components. For a given set, I can draw several samples. Each drawn sample can be either good or bad. My plan is to create a ...
1
vote
1answer
25 views
Classes of asymptotically normal statistics
Consider an iid sample $X_1, \dots, X_n$, from a "well behaved" distribution
with pdf $f(X)$.
My question is the following: what are the classes of statistics $S(X_1, \dots, X_n)$ that are ...
0
votes
0answers
43 views
Best Way to Aggregate Data Into One Value
I've been thinking about ways to aggregate data and was wondering if there is a "proper" statistical route to follow to take information from various variables and combine them into a single ...
0
votes
1answer
34 views
How to understand the variance in this setting?
All -
I have a dataset originated from a practical setting, but it is not clear to me how to interpret it. Let me try to frame the setting and see if it makes sense:
A manufacturer produces a type ...
1
vote
0answers
38 views
Guessing data from statistics
If I have a number of statistics/information of a data set, e.g. mean, SD, skew, kurtosis, % data values within a certain range, etc, how might I go about trying to deduce a portion of the actual ...
0
votes
1answer
134 views
Normalized root mean squared error (NRMSE) vs root mean squared error (RMSE)
The response values in my data set (100 data points) are all positive integers (should not be either negative or zero values). I have developed two statistical models: Linear Regression (LR) and K ...
0
votes
0answers
35 views
what does this +/- of “average” mean?
I have a set of data points and I was told that for it to be valid, every data point should be within +/- say 5% of the average of the entire dataset.
I have no problem of checking each data point ...
0
votes
1answer
52 views
Continue from my previous question - distribution for a set of data using R results
Follow the very useful answers from Peter Flom, Wayne and many others. I have now started using R and it gives me a feeling of python :)
The results are below but I am not sure how should I go from ...
0
votes
2answers
41 views
Finding the distribution when the observations are dependent
How do we find information about the distribution of a variable in presence of dependency among our observations? This dependency is coming from measuring the variable on the same group of subjects ...
1
vote
0answers
24 views
How do I best estimate population parameters from multiple sets of summary statistics on one sample?
Suppose that I have an assortment of summary statistics on a sample, and some beliefs about the underlying distribution, but no access to the sample itself. Each of the sets of summary statistics is ...
2
votes
1answer
74 views
Advice on the statistical analysis of clinical data using summary statistics, t-tests, ANOVA, and linear regression
I need some help with the statistical analysis of a study of a particular surgery to remove a particular cancer. I am using the statistical program R to conduct my analysis. My data are saved in the ...
5
votes
2answers
86 views
What are statistical methods for comparing different brackets
I am not particularly familiar with statistics and am looking at methods for analysing numbers that have been broken into different "brackets" or "groups" for different entities.
Consider three ...
2
votes
1answer
13 views
Macro and Micro Inter-Coder/Rater Agreement
I have a labeling task with 4 labels for which I'm using 2 coders/annotators/raters. This labeling effort leads to a confusion matrix like the one in
...
1
vote
1answer
60 views
Hamming distance for strings with different length
I am working on a project that involves computing similarity metrics between strings. I was would like to know whether it is possible to use hamming distance on strings with differnt length, and if ...
0
votes
0answers
25 views
a compute variable from 2 samples, what to do?
I collected 2 samples from the same 'devices' 256 of them. di and vi.
I want to estimate the Population mean, which would be between 0 and 1 because I compute the variable xi from di and vi as ...
1
vote
0answers
34 views
Study- Probabilities problem
Can some of you tell me why the following holds true?:
$ P(A \& B^C )= P(A)-P(A\&B)$ in which: $ B^C$ is $B$ complement.
In which: $A$ and $B$ are independent.
thanks..
0
votes
4answers
129 views
“The statistician should set the probability of Type I error as low as possible”
Do you agree with the following statement? Why or why not?
I disagree with this statement but i have no reasons to back up.Anyone can help?
0
votes
0answers
10 views
How/why is HUD's FMR (Fair Market Rate) calculated?
This morning I read an article in my local paper called 'Some facts about affordable housing' which covers the National Low Income Housing Coalition's release of their yearly Out of Reach report. ...
2
votes
2answers
144 views
How do I calculate the range that 90% of the values fall into
Given a series of values, I know that 68% of the values fall withing one standard deviation and that 95% fall withing 2 standard deviations, but how do I calculate the range whereby 90% percent of the ...
0
votes
0answers
52 views
How is mean date calculated?
I was surprised to discover yesterday that various summary statistics can be calculated on dates. Googling has found lots on syntax required to calculate summary statistics on dates, but very little ...
0
votes
1answer
71 views
Strange behavior of R function ecdf
I have a very long vector, x, of integer values in the range [0, 1000]. I then use stats::ecdf to create
empirical cummulative ...
1
vote
0answers
37 views
What types of statistical analysis should be done for testing ISP connections?
I'm in the middle of analyzing data taken from testing two different ISP connections (cable and DSL). I've been running randomized testing on the two connection using three different tests which all ...
0
votes
0answers
42 views
Taking the cube root before a correlation when comparing quantities usually bellonging to a skewed distribution?
I was trying to reconcile data the other day just by looking at the cross correlation to see how well it lines up and it was suggested to me that I first apply a cube root transformation given the ...
0
votes
1answer
45 views
Calculating the absenteeism improvement for cabin crew
I have the number of monthly flights, and the number of the active cabin crew in monthly basis, and the number of crew who were absence (sick leave or so) in monthly bases as well. How do I get an ...
4
votes
3answers
175 views
How to describe the differences in skewed data with same median but statistically different distribution?
I am comparing length of stay after laparoscopic and open appendectomy in over 160000 patients. LOS is typically a skewed variable so I use the median and interquartile range and ranksum test to ...
0
votes
1answer
72 views
Summarizing confidence intervals when there are many levels
How can I summarize the confidence intervals for several levels of factors?
This is what I got:
...
3
votes
1answer
69 views
Use of data on a website
I wanted to use some data for statistical analysis available on a company's website. The data is in the form of a time series. Am I allowed to publish my results and conclusions?
5
votes
1answer
73 views
Measure of dispersion over unordered set
I'm looking for a measure of dispersion, such as standard deviation, that can be used when distributing to an unordered set.
Specifically: A bucket distribution assigns a non-negative value to each ...
0
votes
0answers
34 views
Calculating demand size and intervals
could you explain how to determine a the mean and standard deviation of the following: demand size, demand interval and demand per period, with respect to minimum, 25%ile, median, 75%ile and maximum ...
1
vote
0answers
35 views
How to reliably estimate a random sum of unreliable elements?
This is an ill posed problem I'm faced with at work.
I have observations $X_i$, $i = 1,2,3,...N > M$. I need want to compute $S = \sum_{i=1}^M X_i$. Unfortunately, $M$ is random, and extremely ...
2
votes
0answers
57 views
Sample vs. Population
I'm trying to analyse the performance of my server by collecting performance data using standard tools such as Windows Performance Monitor, and then putting this data on Excel for analysis.
When I ...
1
vote
1answer
48 views
Statistical test for finding the effect magnitude of different causes
I am fairly new to statistics and would wish to find out if there is a statistical test that tells me the magnitude/contribution/importance of different causes over a perceived effect.
For example, ...
0
votes
1answer
131 views
Building a summary for values drawn from a bimodal distribution
I have a statistic that assign values to categories of products. This statistic shows strong bimodality (see graph).
For analysis, I am trying to assign a value of that statistic to each product ...
0
votes
2answers
102 views
Question on Survival Analysis
I'm working on a survival analysis project. In part of the project, I'm asked to "identify factors that may contribute to an increased risk of death". I have difficult time understanding what I'm ...
4
votes
1answer
238 views
Measure of variation around Median
Are there terms for measures of variation around the median? I know that we use "variance" for means of data but how can variance be defined for the median? Is there a similar statistic for median?
2
votes
1answer
81 views
A good summary measure on analyzing repeated measures of longitudinal data?
I have an interesting question on longitudinal data and I'm looking for a proper summary measure that enables me to answer my question of interest without knowing/using anything about correlated data. ...
0
votes
0answers
35 views
Statistic describes the sharpness or dispersion of sequential data?
I want to find an existed statistic that can clearly describe the sharpness or dispersion of a peak-shape signal. To state this question more clearly, I plotted two different types (sharp and broad) ...
1
vote
0answers
77 views
What statistics are sufficient?
Can anyone help explain why the following statistics are either Sufficient or not Sufficient?
Mean, Median, Mode, Standard Deviation, Variance, Range, IQR, Skewness, and Kurtosis.
1
vote
1answer
55 views
Average of rate of change in a set of independent change events
What is the right method for computing average of percentage values? Arithmetic average, geometric average, or something else?
Here's an example of problems I'm talking about. Suppose for years 2009, ...
3
votes
0answers
38 views
What type of tool/statistic should I use to inspect two misaligned time series of different granularity?
I have two separate time series, indexed by time in nanoseconds. They both measure the same thing but because they come about in two completely different ways, the number of observations they each ...
0
votes
0answers
150 views
Why odds ratio less than lower limit of 95% confidence interval?
Can there be a situation where odds ratio is less than lower limit of 95% confidence interval? If yes then what could be the possible reason for this? The formula I used to calculate confidence ...
4
votes
4answers
526 views
Ratio of Range to IQR vs. Coefficient of Variation — which is the more useful robust measure?
For a given set of data, spread is often calculated either as the standard deviation or as the IQR (inter-quartile range).
Whereas a standard deviation is ...
0
votes
0answers
65 views
Comparing two opposite ranked sets of data
Looking for the best formula to compare two sets of numbers
Set #1 - Rank: Smaller numbers indicate higher "rank" (Ex: 1 is the best, 1,000,000 is the worst)
Set #2 - Number of Items: The more items ...
5
votes
2answers
134 views
Predictive model & standardized variables
In a predictive model, I have standardized variables as predictors. Say I have to rescore the model on fresh data at some point in the future: do I use the means/stds as they were when I built the ...
1
vote
1answer
131 views
How to compare yearly categorical data?
I have location data from 5 years (>30,000 points). Each location is given a classification name (in my case vegetation classes). These vegetation classes were assigned by intersecting the locations ...
0
votes
0answers
130 views
Need simple calculation for posterior standard deviation of binomial proportions
I'm going to use an example of baseball batting averages to explain what I'm after. Say I have $N$ number of batters, each with a varying number of at-bats $N_i$. So, for example, batter $N_1$ had 5 ...
2
votes
2answers
209 views
Calculating the percentage change of 2 values
If I have two different percentages and I wanted to know the change, I would simply use the percentage change formula...but what if I want to compare two percentages that have different amounts:
Ex: ...
3
votes
1answer
558 views
Estimating misclassification rate from summary classification values
I'm trying to work out the misclassification rate in a published study, where the results do not include this value. However, I have the sensitivity, ...
2
votes
2answers
124 views
Determine range that contains given ratio of data points
I'd like to determine the "representative" range for a series of data points. For example, I'd like to know the range where 98% (or any other given ratio) of points are located. I could have used the ...
