# Questions tagged [data-analysis]

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.

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42 views

### About quantitative analysis, plz help.. [closed]

I have questions below, which i cannot find the problem. Please teach me to follow up the answer. enter image description here
19 views

### Proposed analysis techniques - optimal decision given expectation

I am going to conduct an analysis in order to "weight" different possibilities of actions in a given market. I have an overall level of effort that can be distributed accross the different ...
20 views

### PCA and multi dimensional dataset e.g. Hyperspectral photos [closed]

I do not know why my question was downvoted but let me try one more time. I know the purpose of PCA is to reduce the number of dimension of vector. It finds the space with the highest variance and “...
38 views

### Find formula for a known dataset [migrated]

I am trying to figure out how the computer in this game works. In short: it's like normal monopoly, except instead of owning a property comletely everybody can buy shares for the property (max 9 ...
13 views

### What type of rotational invariance information can I get from interest points (coordinates) of corners from an image?

Assume that you are using the FAST algoritm for corner/feature detection. You pick an image and run the FAST algorithm. Question: All these green dots are actully coordinates in x and y direction. ...
12 views

### Complex Probability with Dependent and Independent Events with conditional

Can I make the simplification: P(D | A ∩ B ∩ C) = P(D | A) ? And if yes, please may i have the proof please ? Or a book where I can find it ? When : D is independant of B and C but it is dependant of ...
26 views

### Linear vs nonlinear interpolation [closed]

I have two questions How does one determine whether to use linear or nonlinear interpolation? Please give examples. Edit: In the case of CDF, say you have CDF numerically and you want to find the ... 14 views

### Is this a useful dimensionality reduction on real projective space?

In the following, I will derive a dimensionality reduction for the real projective space. As I will use scalar product as a means of distance, I am unsure if the dimensionality reduction has a useful ...
1 vote
39 views

### coefficients of the linear model $y=β_0+β_1x_1+β_2x_2$ that minimises the sum of squares error [closed]

Consider the following sample: $$(x_{11}, x_{12}, y_1) = (1, 3, 4),$$$$(x_{21}, x_{22}, y_2) = (2, 1, 5),$$$$(x_{31}, x_{32}, y_3) = (3, 0, 7),$$$$(x_{41}, x_{42}, y_4) = (4, −2, 6).$$ How can I ...
21 views

### linear regression model that uses both input variables $x_1$ and $x_2$ to a given data

Considering the following sample: $$(x_{11}, x_{12}, y_1) = (1, 3, 4), (x_{21}, x_{22}, y_2) = (2, 1, 5), (x_{31}, x_{32}, y_3) = (3, 0, 7).$$ If we fit a multiple linear regression model that uses ...
74 views

### optimisation problem that minimises the sum of absolute errors of the simple linear model $y = a + bx$.

Consider the following sample: $(x_1, y_1) = (1, 1)$, $(x_2, y_2) = (2, 5)$, $(x_3, y_3) = (3, 8)$, $(x_4, y_4) = (4, 18)$. How can I write down an optimisation problem that minimises the sum of ...
52 views

### Calculating the RMSE and $R^2$ with a linear model $y = a + bx$ so that the mean squared error of the model is minimised [closed]

Consider the following sample: $(x_1, y_1) = (1, 1)$, $(x_2, y_2) = (2, 5)$, $(x_3, y_3) = (3, 8)$, $(x_4, y_4) = (4, 18)$. Suppose you predict $y$ based on $x$ with a linear model $y = a + bx$ so ...
64 views

### logistic regression model to calculate the log odds

Let’s say that you have estimated the following logistic regression model to calculate the log odds of a $4$ year old child being obese $(y = 1)$ using the independent variable weight in kgs $(x)$: ...
52 views

### calculate all pairwise dot (inner) products between data points

Suppose we have $n$ data points in $\mathbb{R}^p$ and we would like to calculate all pairwise dot (inner) products between them. How can I write a single matrix multiplication that does this? (Some ...
12 views

### Test normality from histogram data

I have histogram data that I'd like to formally test for normality but I don't have the actual data points that generated the histogram. The histogram looks something like this: Is there a standard ...
26 views

### Using Bayesian statistics in time series forecasting

I would like to forecast demand count time series of taxi fleets at different locations on the map at different points in time. I.e. multivariate demand Time series forecasting. Given hierarchinal ...
1 vote
36 views

### Persistence Vector Spaces

I am currently reading Gunnar Carlsson's "Topological Pattern Recognition for Point Cloud Data", you can find it here: http://math.stanford.edu/~gunnar/actanumericathree.pdf I have a ...
56 views

### How to make the income distribution of a country follows the 80:20 rule?

My main question: Let's imagine a country with a population of $n$ people. Each person has a certain amount of income in a certain year. When we calculate the income distribution of this country, we ...
51 views

1 vote
31 views

### Function form to fit a nonlinear trend

I'm trying to guess a function that would fit the non-oscillating part of the following curve: I tried something in the form of $y = 1 - e^{-ax}$ and $tan^{-1}(ax)$, but it didn't work since the ...
15 views

### Modeling Regional Quality Based on SUM of GCL / SUM of TAP - Comparing Two Approaches

I'm learning Data Science and I'm currently working on analyzing loan data across different regions. My goal is to build a model that can assess the quality of a given region based on the ratio \...
14 views

### Unifying multiple sample data

I would like to unify multiple sample data (of different sizes) into some "unified sample" to evaluate its collective variance. Is this something statisticians do? I thought of unifying ...
12 views

### Modeling Fog Formation Percentage with Exponential Decay Based on Dew Point Depression and Wind Speed

I am working with a 15-minute time series dataset that includes columns for Dew Point Depression and Wind Speed. Utilizing specific conditions based on these columns, I've successfully categorized fog ...
22 views

### Exponential Power Fit

I have 3 data points for a material property (permeability of a gas through an solid elastomer) as a function of temperature. My goal is to extrapolate the property at a lower temperature. As a ...
11 views

### Ranking drivers of change in a time dependent weighted average

Let $C(t)$ be a discrete, finite set of Customer IDs with $|C(t)| =n(t) >0$ denoting the number of customers in the set at time $t \in \mathbb{N}$. Consider the following time-dependent weighted ...
55 views

### Normalizing Euclidean distance by the length of the vectors

Suppose I have 4 vectors, the first 2 vectors are of length 4 and the last 2 vectors are of length 400. all values in the vectors range from 0.5 to 0.6. The Euclidean distance between the last 2 ...
1 vote
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### Center of Sums method - centroid of different shapes question

I'm doing fuzzy logic and I need to use the center of sums method to calculate a value. I have the graph of functions here: Sorry for the low quality, but I think this suffices. The formula is with ...