• ## R data analysis: visual interpretation of mixed effect model. If you don’t understand it, you really can’t help it

Time：2022-2-15

Many students asked me about the mixed effect model. They need to talk about some problems many times. Just think about it and post it again. Try to write this article clearly for you. Mixed effect models have many names,Hierarchical Modeling, also known as Mixed Effects Modeling，There are hierarchical models, hierarchical regression models, stochastic models […]

• ## [Luogu p3961, tjoi2013] gold miners

Time：2022-2-7

This is undoubtedly a grouping knapsack problem. The slope is the basis of grouping, and the items in the group are the prefix and sum of the value and weight of gold bullion under this slope. It is found that many people use double to store the slope. In fact, we can save it by […]

• ## 40 statistical basis – maximum likelihood of normal distribution

Time：2022-1-6

The following figure isNormal distributionThe equation has two parameters. The first parameter is the Greek alphabetμ, it determines the normal distributionaverage value(mean), μ The smaller the value of, the mean value of the distribution will move to the left, μ The greater the value of, the more the mean value of the distribution shifts to […]

• ## [ACM training] DP problem of slope optimization

Time：2021-11-20

Luogu p3195 [hnoi2008] toy packing Topic introduction Link:https://www.luogu.com.cn/prob… shopping spree Solution I (TLE) First write the violent version DP #include <iostream> #include <algorithm> typedef long long ll; #define read(x) scanf(“%lld”, &x) using namespace std; const int N = 50010; ll sumc[N], f[N], n, L; int main() { read(n); read(L); ll c; for (int i = […]

• ## R data analysis: simple slope mapping and interpretation of bicontinuous variable interaction

Time：2021-11-10

Interaction: When the effect of one independent variable differs based on the level or magnitude of another independent variable I believe many people are familiar with the interaction, and it often appears in the paper. You will also want to see the interaction between the variables of interest,Interaction means that at different levels of one […]

• ## Professional English commonly used in Mathematics

Time：2021-11-2

AccelerationCalculusCalculation, estimationCancellation cancellationContinuityConstants constantDeduce calculationDerivative derivativedelta △A removable singularity is a removable breakpointFormulaGeometric geometricGradient gradientGravity; Gravity; seriousnessInstantaneous rateJump discontinuityLimit limitMake sense out ofParameter, parameter, determinant, boundaryRatioSlope slopeTangent tangentThe average rate of changeThe left hand limitThe right hand limitThe initial positionVariable variable20 meters a second 20m/s This work adoptsCC agreement, reprint must indicate the author and […]

• ## Python Bayesian regression analysis of housing affordability data set

Time：2021-8-26

Original link:http://tecdat.cn/?p=11664  I want to study how to use pymc3 for linear regression within the Bayesian framework. Infer from the knowledge learned from the data. What is the Bayesian rule? In essence, we must combine what we already know with the facts of the world. Here is an example. Assuming the existence of this rare […]

• ## Extension data tecdat: R language Econometrics: application of dummy variables (dummy variables) in linear regression model

Time：2021-8-8

Original link:http://tecdat.cn/?p=22805  Why do I need dummy variables? Most data can be measured by numbers, such as height and weight. However, variables such as gender, season and location cannot be measured numerically. Instead, we use dummy variables to measure them. Example: Gender Let’s assume that the effect of X on y is different between men […]

• ## R language Stan for Bayesian reasoning analysis

Time：2021-4-23

Link to the original text:http://tecdat.cn/?p=6252 Stan of R Stan can be run from many statistical packages. So far, I’ve been running Stan from R. Simple linear regression The first step is to document the Stan model. This contains a file linreg.stan ： data { int N; vector[N] x; vector[N] y; } model { y ~ […]

• ## Eight queens problem — recursive backtracking

Time：2021-1-30

1. Eight queens Put eight queens on the 8 × 8 chessboard so that they can’t attack each other, that is, any two Queens can’t be in the same row, the same column or the same diagonal line. How many kinds of pendulum are there. 2. Ideas This problem is very suitable to be solved […]

• ## Array of algorithms — the maximum number of points in a common line

Time：2020-11-20

The maximum number of points on a line difficultydifficulty Given a two-dimensional plane, there are n points on the plane, find the maximum number of points on the same line. Example 1:Input: [[1,1],[2,2],[3,3]]Output: 3Explanation: Example 2:Input: [[1,1],[3,2],[5,3],[4,1],[2,3],[1,4]]Output: 4Explanation: thinking First, you need to make sure that two points are on a straight line – that […]

• ## JS + CSS3 to achieve image slider effect

Time：2020-7-8

effect Analyzing the animation can be divided into two steps: Add an animation class when the mouse moves in or out Realize the animation class and move in and out animation Picture waterfall flow layout can refer to Vue handwritten picture waterfall flow component (with source code) HTML and CSS layout The layout is relatively […]