Questions on the use of mathematical techniques to extract properties from given data. Consider if your question might be more suited for Cross Validated (stats.SE) instead.

learn more… | top users | synonyms

3
votes
1answer
19 views

Median of Medians

Given a set A with median Am = 10 and set B with median Bm = 20 is it true that the median of the combined set C is $10 \le$ Cm$\le 20$ ? My first thought was that this wasn't true so I tried to find ...
2
votes
5answers
36 views

Prove a function is in Big-Oh and not in Big-Omega

We are told to use the definitions of Big-Oh and Big-Omega to prove that a given function is in $O(f(n))$ or $\Omega(f(n))$. It requires being able to use $c$ and $n_0$. Use the definitions to show ...
2
votes
1answer
43 views

Obtaining quadratic equation using Least Squares Method

This question is most likely extremely trivial, but I'm having some difficulty obtaining the least squares equation from the following data points: {{1.08, 0}, {1.07, 0.0659232}, {0.97, 0.1695168}, ...
1
vote
0answers
32 views

Mixing Fuzzy Logic and Probabilistic interpretation of a dataset

A probabilistic data cloud is a set $M$ of data points $\{m_i\}_i$, where each data point $m_i$ is associated to an event $E_i$ expressing the set of the occurrences of $m_i$ in any possible ...
0
votes
0answers
17 views

Fit a curve to Data in R [closed]

I'm fairly new to R, and attempting to fit a curve to a super simple set of data I have. I've tried nls but can't seem to get it correct. My data is as follows: ...
0
votes
0answers
17 views

Relationship/correlation between data - does it exist?

Data I refer to in this question Some analysis has been conducted for my business by an external company. The data, as it stands, only really tells part of the story and doesn't provide any real ...
0
votes
1answer
25 views

Finding relation between inputs and outputs

Is anyone able to find the rule? If possible, can you explain how and what's the name of that kind of rule? Input Output 0,18 0,316 0,3 0,432 0,32 0,4536 0,33 0,4644 0,34 ...
0
votes
0answers
14 views

Continuous/interpolating alternative to order of magnitude?

Define $\operatorname{magnitude}\left(x\right) = 10 ^ { \lfloor \log_{10} x \rfloor }$ and $\operatorname{magnitude'}\left(x\right) = 10 ^ { \lfloor \log_{10} x \rceil }$ Currently I'm using this ...
3
votes
2answers
48 views

How to pick the “best” line equation that fits data and passes through the origin?

I have some data shown in the image. Each symbol corresponds to a different dataset. As it can be seen the data initially behaves like a line and after some points it follows other behaviour. The ...
0
votes
1answer
25 views

calculation of median of grouped data

While calculating the median of grouped data of total frequency $N$, in order to find the median class which value should be taken into consideration to match against cumulative frequency : $\frac N2$ ...
0
votes
0answers
24 views

Euclidean Distance in Non-orthogonal system

I'm taking a beginner's course at university on the Data Analysis subject and I'm struggling with this exercise. Maybe someone would be kind enough to help me understand it and solve it. "Considering ...
2
votes
1answer
36 views

Fitting a curve given points

My set-up is the following, I have two variables $N$ and $TTR$, and I have these points for each variable: $N$ = [35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50] $TTR$ = [0.818, ...
0
votes
0answers
9 views

Distribution for frequency data

I am conducting statistical tests on a large set of frequency data. The frequency data is in the form of times of occurrence of events at a number of locations. Locations can be assumed to be ...
-1
votes
0answers
17 views

Can I/ How to conduct logistic regression on non-binary data?

I have collected data points from an experiment. The data' domain is [0,312] and range is [0,98]. I know a logistics function will fit the data very well. I performed the logistics regression on my ...
0
votes
1answer
22 views

Finding the number that's less than 90% of result set

Forgive if this sounds vague or poorly worded. I'm struggling to pinpoint the right terminology of what I'm looking to do. Hoping someone here can push me in the right direction. So I have a set of ...
0
votes
1answer
55 views

Determine equation from graph

Background: I'm working on a script to read/parse a file generated by a piece of software I use to create music mixes. One aspect I'm having difficulty with is translating the volume value from it's ...
0
votes
0answers
32 views

Calculating Average “Productivity”

Let me apologise in advance if my terminology is incorrect or if what seems logical to me is completely nonsensical. I am an analyst without a mathematical background and have tried to self teach off ...
1
vote
2answers
23 views

How sensitive is a natural cubic spline?

I am interested in using natural cubic splines to generate possible replacement values in the quality control of data. I would like to do this as close to real-time as I can. That is, I would like ...
1
vote
1answer
27 views

How to describe a statistical dataset more precisely?

I am a newbie in stat and I need to be able to do this for a GIS application: Say I have the following dataset of only two possible values $0$ and $1$: $0,0,0,1,1,1,0,1$ The mean would equal ...
0
votes
0answers
15 views

Is data normally distributed over attributes or need to be normalized ( scale )

I have been spend lot of time related to my data distribution, for the following matrix, there are need to cluster similar factories as follow : - each factory made some products for example : factory ...
1
vote
1answer
76 views

On normalized error measures

I have function values $f_1,\ldots,f_n$ that are approximated by data $y_1,\ldots,y_n$. I am looking for a measure that describes the error in the data $y_1,\ldots,y_n$ and I want the measure to take ...
0
votes
0answers
13 views

replicating a probability model for classification

I'm trying to replicate a probability model for a binary classification based on some data. Until now I been able to replicate the left panel, the histogram and the gaussians curves, but I dont know ...
0
votes
0answers
7 views

Building agglomerative hierarchical clustering algorithm manually

I am currently trying to solve this problem but I'm quite unsure if my answer is correct. I've build the tree different types of measures, MIN, MAX and AVERAGE but I might have some of them wrong. Can ...
0
votes
0answers
10 views

Complementation Rule for MVDs

I have that $X \rightarrow \rightarrow Y$ is a Multivalued Dependency in $R$ and let $Z=R-(X \cup Y)$ With $t_{1}[x]=t_{2}[x]=t_{3}[x]=t_{4}[x]$ $t_{1}[y]=t_{3}[y]$ and $t_{2}[y]=t_{4}[y]$ ...
0
votes
0answers
6 views

Comparing Temperature Curves

I'm collecting a bunch of temperature data from water cool down tests and need some advice on how to best compare data from different tests. I have a test stand and as I change test variables between ...
0
votes
0answers
13 views

Bayesian model to estimate the parameter of a Bernoulli law

Suppose we have iid boolean variables $X_1,...,X_T = X_{1:T}$ and the associated deterministic parameters $k_1,...,k_T=k_{1:T}$ and $c_1,...,c_T=c_{1:T}$, where for each $t \in \mathbb{N}$, $k_{t} \in ...
1
vote
1answer
45 views

Stem and Leaf Plot for Strongly Skewed Data

How to draw a stem and leaf plot for the following large data, the data is for different EU states so there is a large difference between the data. I have to plot stem and leaf for each table i.e. ...
1
vote
1answer
33 views

File Compression Statistics

Statically, how is the compression of a file possible? As in, a file n bytes long can have $2^{n*8}$ (the 'times 8' part is because there are 8 bits in a byte). So, if you decrease the size then ...
0
votes
0answers
13 views

How to know whether the data is linear separable?

The data has many features (e.g. 100) and the number of instances is like 100,000. The data is sparse. I want to fit the data using logistic regression or svm. How do I know whether features are ...
0
votes
0answers
14 views

Need explanation on normalising data between 0 and 1

I have two columns of data which are of very different size ranges. So I decided to normalise them to be within the range 0 and 1. Could someone explain what doing this actually means for my ...
0
votes
0answers
12 views

Data Management Frequency Interval

I am given the results of 30 students for a Data Management test: $78, 81, 55, 60, 65, 86, 44, 90, 59, 81, 77, 71, 65, 39, 80, 72, 70, 64, 68, 78, 88, 73, 61, 70, 75, 96, 51, 73, 65, 67.$ The ...
0
votes
0answers
18 views

Ordinal scale: does aggregating data by arithmetic mean is a concrete problem?

Sometimes when people have some ordinal values, they use a misleading number representation. Then, they aggregate data with arithmetic mean. For example, we have to aggregate the grades of an exam ...
0
votes
0answers
9 views

Introducing weights into spectral clustering

Suppose I have a data set with points $x_i$ and a dissimilarity measure $d_{ij}$ between each pair, as well as a weight $w_{ij}$ that qualifies the quality of this dissimilarity. I have two problems: ...
0
votes
0answers
24 views

How to do Modified Mann Kendall test for trend analysis?

In mann Kendal trend analysis if auto-correlation in the time series exist we do pre-whitening to remove the affect of lag-1 correlation. However, it has been reported that pre-whitening reduces the ...
0
votes
0answers
13 views

Find repeated attribute patterns in collection of objects

I have objects $o_1,...,o_k$where every object has a set of properties $p_1,...,p_j$. I'm looking for property patterns that are repeated among these objects. It could be perhaps called correlation of ...
0
votes
0answers
18 views

Ortogonal polynomial regression

I need to fit a weighted set of points with orthogonal polynomials based on least squares polynomials. The grid on X is nonuniform, so Chebyshev polynomials can't be applied. The data points are like ...
1
vote
1answer
48 views

Cauchy Schwarz inequality in Normalized Cross Correlation

I'm currently using a normalized cross correlation(NCC) for measure the degree of similarity between two image. Almost two week studying about how NCC is derived from Cauchy Schwarz inequality but ...
0
votes
0answers
13 views

Cohen's Kappa and MovieLens

I'm tryings to analyse the MoveLens 20m data set and I'm interested at looking at user rating agreement levels. Someone has suggested I look at Cohen's Kappa as this kind of inter-rater agreement is ...
0
votes
1answer
19 views

What would be a good algorithm to determine the busiest servers by cpu usage

I have a huge data set that contains time series data for some servers' cpu usage per application. I need to find the busiest servers to for the application and print it. I need to find a method or ...
1
vote
0answers
15 views

Penalty function of multi-peak fit?

The question I have is about the answer from here by @Silvia: http://mathematica.stackexchange.com/questions/26336/how-to-perform-a-multi-peak-fitting I can only understand some of the code but the ...
1
vote
2answers
63 views

What is the order of this algorithm?

I was messing around with a method of manipulating strings in Java when I came across this algorithm. For a string of length n: $$\{1, 2, ... ,n - 1, n\}$$ rearrange it such that the first character ...
0
votes
1answer
40 views

Create a modal line or benchmark

I have some data the following, X is cycle in percentage, and Y is the quantity: ...
2
votes
1answer
36 views

Mean of values ${1 \over m} {\sum_{i=1}^m {s_i \over t_i}}$ vs. Value of sums ${\sum_{i=1}^m {s_i} \over \sum_{i=1}^m {t_i}}$, What is the relation?

Similar to: Average of products VS. product of averages I have $$ R = \{(s_1, t_1), (s_2, t_2), ..., (s_n, t_n)\} $$ With the property that, for all pairs $(s_i, t_i)$, $0 \le s_i < t_i$. $$ ...
0
votes
1answer
28 views

Runge-Kutta (Fehlberg) with multiple time dependant variables and adaptive time steps

I've searched the internet for weeks for a step in the right direction with this. I'm trying to solve a first order ODE- not too difficult I know, and I am capable thus far of implementing the Runge ...
2
votes
1answer
41 views

Distance between unequal-dimension vectors (and data)?

It is easy to find simple distance measures for equal-dimension vectors, such as Euclidean Distance or Correlation. What about unequal-dimension vectors, such as, for instance, $(a,b,c)$ and $(d,e)$? ...
0
votes
0answers
15 views

Find the 9Bit key for a 3 round toy DES cipher

Differential Analysis I am having a difficult time to understand and find a solution to the key. As you might have noticed the last 6 digits (000 111) of the plain text are same. All the below ...
2
votes
1answer
19 views

Extrapolate data points from a series of averages

Given a series of data points: $$\begin{array}{c|c|c|c|c|c|c|c|} & \text{Monday} & \text{Tuesday} & \text{Wednesday} & \text{Thursday} & \text{Friday} & \text{Saturday} ...
0
votes
0answers
21 views

How to infer information from a cumulative frequency graph, and what it means practically

So I'm given a table of data, regarding "An estimator working for a large construction company, is preparing a tender and trying to establish a rate for reinforcing bars in a concrete floor. Data ...
0
votes
0answers
18 views

Is the sum of all cross-correlation samples representative of target existence likelihood?

Answers to this question take the peak in the cross correlation as the measure to the likelihood of the trigger signal exist in the received signal - this is pretty much text book. My question is ...
1
vote
1answer
31 views

Find errored member in a dataset

Assuming a simple data-set looking like this dataset As you can see there is 10 lines, each one representing an entity. For each entity, there is an amount of downloaded and uploaded data which are ...