Update: Solved!
I'm currently trying to create a regression model for football that predicts a team's total points based on their pass yards and rush yards. I was able to get all the way to figuring out the regression equation but from here I do not know how to "plug in" the formula.
The data table is essentially all 32 NFL teams listed in rows and their offensive stats listed in columns
Code:
# 1. Import
Offense <- read.csv(file.choose(), header=TRUE)
#2 View
show (Offense)
#3 Attach so headers can be referenced
attach (Offense)
#4 Create Regression Model
mod1 <-lm(Total.Points ~ Pass.Yds + Rush.Yds)
summary(mod1)
#Formula obtained from summary: -255.60178 + .10565(Pass) + .12154(Rush)
#Plug in the Regression Equation
predict(mod1)
Output: https://imgur.com/a/AbTNF
I see that at the end it applied the regression equation to all 32 rows, but how do I
get it to display in a ranked list
get it to display, say, the team name as well as the projected score (so I don't have to wonder what team "1" or "2" refer to
Since I have the equation, could I also just write a loop function that ran the equation for every row of data I have and print the results?
I'm a beginner so much appreciated!
Update: Came up with this
####Part 2. Interpretation
#1. Examining quality of model
summary(mod1)
cor(Pass.Yds, Rush.Yds)
#2. Formula obtained from summary: -255.60178 + .10565(Pass) + .12154(Rush)
#3. Predicted Points (Descending Order)
proj <- sort(predict(mod1), decreasing = TRUE)
proj
#4. Corresponding Name (Descending)
name <- Team[order(predict(mod1), decreasing = TRUE)]
name
#Data Frame
Projections <- data.frame(name, proj)
Projections
While bbrot provided a much simpler version
Assuming that Teams is the vector of team names, something like cbind(Teams[order(predict(mod1), decreasing = TRUE)], sort(predict(mod1), decreasing = TRUE)) should do...
Edit: Your Teams vector seems to be a factor. In this case, the following commands are going to work:
# returns a character matrix
cbind(as.character(Teams)[order(predict(mod1), decreasing = TRUE)],
sort(predict(mod1), decreasing = TRUE))
# returns a data frame
data.frame(Teams = Teams[order(predict(mod1), decreasing = TRUE)],
Points = sort(predict(mod1), decreasing = TRUE))
Related
I am performing a PLS-DA analysis in R using the mixOmics package. I have one binary Y variable (presence or absence of wetland) and 21 continuous predictor variables (X) with values ranging from 1 to 100.
I have made the model with the data_training dataset and want to predict new outcomes with the data_validation dataset. These datasets have exactly the same structure.
My code looks like:
library(mixOmics)
model.plsda<-plsda(X,Y, ncomp = 10)
myPredictions <- predict(model.plsda, newdata = data_validation[,-1], dist = "max.dist")
I want to predict the outcome based on 10, 9, 8, ... to 2 principal components. By using the get.confusion_matrix function, I want to estimate the error rate for every number of principal components.
prediction <- myPredictions$class$max.dist[,10] #prediction based on 10 components
confusion.mat = get.confusion_matrix(truth = data_validatie[,1], predicted = prediction)
get.BER(confusion.mat)
I can do this seperately for 10 times, but I want do that a little faster. Therefore I was thinking of making a list with the results of prediction for every number of components...
library(BBmisc)
prediction_test <- myPredictions$class$max.dist
predictions_components <- convertColsToList(prediction_test, name.list = T, name.vector = T, factors.as.char = T)
...and then using lapply with the get.confusion_matrix and get.BER function. But then I don't know how to do that. I have searched on the internet, but I can't find a solution that works. How can I do this?
Many thanks for your help!
Without reproducible there is no way to test this but you need to convert the code you want to run each time into a function. Something like this:
confmat <- function(x) {
prediction <- myPredictions$class$max.dist[,x] #prediction based on 10 components
confusion.mat = get.confusion_matrix(truth = data_validatie[,1], predicted = prediction)
get.BER(confusion.mat)
}
Now lapply:
results <- lapply(10:2, confmat)
That will return a list with the get.BER results for each number of PCs so results[[1]] will be the results for 10 PCs. You will not get values for prediction or confusionmat unless they are included in the results returned by get.BER. If you want all of that, you need to replace the last line to the function with return(list(prediction, confusionmat, get.BER(confusion.mat)). This will produce a list of the lists so that results[[1]][[1]] will be the results of prediction for 10 PCs and results[[1]][[2]] and results[[1]][[3]] will be confusionmat and get.BER(confusion.mat) respectively.
I am new to R and I am using glm() function to fit a logistic model. I have 5 columns. I need to find all possible predictors using a loop based on their p-values(less than 0.05).
My dataset has 40,000 entries which contains numerical and categorical variables and it looks more or less like this:
"Age" "Sex" "Occupation" "Education" "Income"
50 Male Farmer High School False
30 Female Maid High School False
25 Male Engineer Graduate True
The target variable "Income" denotes if the person earns more or less than 30K. If true means, they earn more than 30K and vice versa. I would like to find the predictor variables that can be used to predict the target using loops. Also, can I find the best 3 predictors based on their p-values?
Thanks in Advance!
If I understood correctly your question you are looking into a way of test univariable models given your dataframe (i am in fact in doubt if you want to test every combination of these variables including cross variation)
My suggestion is to use purrr::map function and create list for every column. Check the following example based on your information:
library(tidyr)
library(purrr)
## Sample data
df <- data.frame(
Age = rnorm(n = 40000,
mean = mean(c(50,30,25)),
sd(c(50,30,25))),
Ocupation = sample(x = c("Farmer", "Maid", "Engineer"),
size = 40000,
replace = TRUE),
Education = sample(x = c("High School", "Graduate", "UnderGraduate"),
size = 40000,
replace = TRUE),
Income = as.logical(rbinom(40000, 1, 0.5))
)
## Split dataframe into lists
list_df <- Map(cbind, split.default(df[-4], names(df)[-4]))
list_df <- lapply(list_df, cbind, "target" = df[4])
## Use map to fit a model for each list
list_models <- map(.x = list_df,
.f = ~glm(Income ~ ., data = .x, family = binomial))
You can call each model using list_models[i].
Now addressing the second part of your question concerning p-values. Given that each project is unique and so are their metrics i suggest you double check you usage of p-values. Granted, they are important, but they provid you a probability of acceptance given a specific statistic test and treshold which depends on context. It is a fundamental tool of statistical quality and decision (not only about t-test, but f-test and hence forward). But for ranking ? hmm i would say is a litle odd. But just saying :)
I’m working on a DEA (Data Envelopment Analysis) analysis to analyze the relative effects of different banks efficiencies.
The packages I’m using are rDEA and kableExtra.
What this analysis if doing is measuring the relative effect of input and output variables that I use to examine the efficiency for each individual bank.
The problem is that my code only includes two out of four output variables and I can’t find anywhere in the code where I ask it to do so.
Can some of you identify the problem?
Thank you in advance!
I have tried to format the data in several different ways, assign the created "inp_var" and "out_var" as a matrix'.
#install.packages('rDEA')
#install.packages('dplyr')
#install.packages('kableExtra')
library(kableExtra)
library(rDEA)
library(dplyr)
dea <- tbl_df(PANELDATA)
head(dea)
inp_var <- select(dea, 'IE', 'NIE')
out_var <- select(dea, 'L', 'D', 'II','NII')
inp_var <- as.matrix(inp_var)
out_var <- as.matrix(out_var)
model <- dea(XREF= inp_var, YREF = out_var, X = inp_var, Y = out_var, model= "output", RTS = "constant")
model
I want a number between 0 and 1 for every observation, where the most efficient one receives a 1. What I get now is the same result no matter if I include the two extra output variables L and II or not.
L stands for Loans to the public and II for interest income and it would be weird if these variables had NO effect for the efficiency of banks.
I think you could type this:
result <- cbind(round(model$thetaOpt, 3), round(model$lambda, 3))
rownames(result)<-dea[[1]]
colnames(result)<-c("Efficiency", rownames(result))
kable(result[,])
I received some good help getting my data formatted properly produce a multinomial logistic model with mlogit here (Formatting data for mlogit)
However, I'm trying now to analyze the effects of covariates in my model. I find the help file in mlogit.effects() to be not very informative. One of the problems is that the model appears to produce a lot of rows of NAs (see below, index(mod1) ).
Can anyone clarify why my data is producing those NAs?
Can anyone help me get mlogit.effects to work with the data below?
I would consider shifting the analysis to multinom(). However, I can't figure out how to format the data to fit the formula for use multinom(). My data is a series of rankings of seven different items (Accessible, Information, Trade offs, Debate, Social and Responsive) Would I just model whatever they picked as their first rank and ignore what they chose in other ranks? I can get that information.
Reproducible code is below:
#Loadpackages
library(RCurl)
library(mlogit)
library(tidyr)
library(dplyr)
#URL where data is stored
dat.url <- 'https://raw.githubusercontent.com/sjkiss/Survey/master/mlogit.out.csv'
#Get data
dat <- read.csv(dat.url)
#Complete cases only as it seems mlogit cannot handle missing values or tied data which in this case you might get because of median imputation
dat <- dat[complete.cases(dat),]
#Change the choice index variable (X) to have no interruptions, as a result of removing some incomplete cases
dat$X <- seq(1,nrow(dat),1)
#Tidy data to get it into long format
dat.out <- dat %>%
gather(Open, Rank, -c(1,9:12)) %>%
arrange(X, Open, Rank)
#Create mlogit object
mlogit.out <- mlogit.data(dat.out, shape='long',alt.var='Open',choice='Rank', ranked=TRUE,chid.var='X')
#Fit Model
mod1 <- mlogit(Rank~1|gender+age+economic+Job,data=mlogit.out)
Here is my attempt to set up a data frame similar to the one portrayed in the help file. It doesnt work. I confess although I know the apply family pretty well, tapply is murky to me.
with(mlogit.out, data.frame(economic=tapply(economic, index(mod1)$alt, mean)))
Compare from the help:
data("Fishing", package = "mlogit")
Fish <- mlogit.data(Fishing, varying = c(2:9), shape = "wide", choice = "mode")
m <- mlogit(mode ~ price | income | catch, data = Fish)
# compute a data.frame containing the mean value of the covariates in
# the sample data in the help file for effects
z <- with(Fish, data.frame(price = tapply(price, index(m)$alt, mean),
catch = tapply(catch, index(m)$alt, mean),
income = mean(income)))
# compute the marginal effects (the second one is an elasticity
effects(m, covariate = "income", data = z)
I'll try Option 3 and switch to multinom(). This code will model the log-odds of ranking an item as 1st, compared to a reference item (e.g., "Debate" in the code below). With K = 7 items, if we call the reference item ItemK, then we're modeling
log[ Pr(Itemk is 1st) / Pr(ItemK is 1st) ] = αk + xTβk
for k = 1,...,K-1, where Itemk is one of the other (i.e. non-reference) items. The choice of reference level will affect the coefficients and their interpretation, but it will not affect the predicted probabilities. (Same story for reference levels for the categorical predictor variables.)
I'll also mention that I'm handling missing data a bit differently here than in your original code. Since my model only needs to know which item gets ranked 1st, I only need to throw out records where that info is missing. (E.g., in the original dataset record #43 has "Information" ranked 1st, so we can use this record even though 3 other items are NA.)
# Get data
dat.url <- 'https://raw.githubusercontent.com/sjkiss/Survey/master/mlogit.out.csv'
dat <- read.csv(dat.url)
# dataframe showing which item is ranked #1
ranks <- (dat[,2:8] == 1)
# for each combination of predictor variable values, count
# how many times each item was ranked #1
dat2 <- aggregate(ranks, by=dat[,9:12], sum, na.rm=TRUE)
# remove cases that didn't rank anything as #1 (due to NAs in original data)
dat3 <- dat2[rowSums(dat2[,5:11])>0,]
# (optional) set the reference levels for the categorical predictors
dat3$gender <- relevel(dat3$gender, ref="Female")
dat3$Job <- relevel(dat3$Job, ref="Government backbencher")
# response matrix in format needed for multinom()
response <- as.matrix(dat3[,5:11])
# (optional) set the reference level for the response by changing
# the column order
ref <- "Debate"
ref.index <- match(ref, colnames(response))
response <- response[,c(ref.index,(1:ncol(response))[-ref.index])]
# fit model (note that age & economic are continuous, while gender &
# Job are categorical)
library(nnet)
fit1 <- multinom(response ~ economic + gender + age + Job, data=dat3)
# print some results
summary(fit1)
coef(fit1)
cbind(dat3[,1:4], round(fitted(fit1),3)) # predicted probabilities
I didn't do any diagnostics, so I make no claim that the model used here provides a good fit.
You are working with Ranked Data, not just Multinomial Choice Data. The structure for the Ranked data in mlogit is that first set of records for a person are all options, then the second is all options except the one ranked first, and so on. But the index assumes equal number of options each time. So a bunch of NAs. We just need to get rid of them.
> with(mlogit.out, data.frame(economic=tapply(economic, index(mod1)$alt[complete.cases(index(mod1)$alt)], mean)))
economic
Accessible 5.13
Debate 4.97
Information 5.08
Officials 4.92
Responsive 5.09
Social 4.91
Trade.Offs 4.91
I'm trying to generate estimates of the percent of Catholics within a given municipality in a country and I'm using multilevel regression and post-stratification of survey data.
The approach fits a multilevel logit and generates predicted probabilities of the dependent variable. It then weights the probabilities using poststratification of the sample to census data.
I can generate the initial estimates (which are essentially just the predicted probability of being Catholic for a given individual in the survey data.) However, when I try to take the average with the last line of code below it only returns NA's for each of the municipalities. The initial cell predictions have some missing values but nowhere near a majority.
I don't understand why I can't generate municipal weighted averages as I've followed the procedure using different data. Any help would be greatly appreciated.
rm(list=ls(all=TRUE))
library("arm")
library("foreign")
#read in megapoll and attach
ES.data <- read.dta("ES4.dta", convert.underscore = TRUE)
#read in municipal-level dataset
munilevel <- read.dta("election.dta",convert.underscore = TRUE)
munilevel <- munilevel[order(munilevel$municode),]
#read in Census data
Census <- read.dta("poststratification4.dta",convert.underscore = TRUE)
Census <- Census[order(Census$municode),]
Census$municode <- match(Census$municode, munilevel$municode)
#Create index variables
#At level of megapoll
ES.data$ur.female <- (ES.data$female *2) + ES.data$ur
ES.data$age.edr <- 6 * (ES.data$age -1) + ES.data$edr
#At census level (same coding as above for all variables)
Census$cur.cfemale <- (Census$cfemale *2) + Census$cur
Census$cage.cedr <- 6 * (Census$cage -1) + Census$cedr
##Municipal level variables
Census$c.arena<- munilevel$c.arena[Census$municode]
Census$c.fmln <- munilevel$c.fmln[Census$municode]
#run individual-level opinion model
individual.model1 <- glmer(formula = catholic ~ (1|ur.female) + (1|age)
+ (1|edr) + (1|age.edr) + (1|municode) + p.arena +p.fmln
,data=ES.data, family=binomial(link="logit"))
display(individual.model1)
#examine random effects and standard errors for urban-female
ranef(individual.model1)$ur.female
se.ranef(individual.model1)$ur.female
#create vector of state ranefs and then fill in missing ones
muni.ranefs <- array(NA,c(66,1))
dimnames(muni.ranefs) <- list(c(munilevel$municode),"effect")
for(i in munilevel$municode){
muni.ranefs[i,1] <- ranef(individual.model1)$municode[i,1]
}
muni.ranefs[,1][is.na(muni.ranefs[,1])] <- 0 #set states with missing REs (b/c not in data) to zero
#create a prediction for each cell in Census data
cellpred1 <- invlogit(fixef(individual.model1)["(Intercept)"]
+ranef(individual.model1)$ur.female[Census$cur.cfemale,1]
+ranef(individual.model1)$age[Census$cage,1]
+ranef(individual.model1)$edr[Census$cedr,1]
+ranef(individual.model1)$age.edr[Census$cage.cedr,1]
+muni.ranefs[Census$municode,1]
+(fixef(individual.model1)["p.fmln"] *Census$c.fmln) # municipal level
+(fixef(individual.model1)["p.arena"] *Census$c.arena)) # municipal level
#weights the prediction by the freq of cell
cellpredweighted1 <- cellpred1 * Census$cpercent.muni
#calculates the percent within each municipality (weighted average of responses)
munipred <- 100* as.vector(tapply(cellpredweighted1, Census$municode, sum))
munipred
The extensive amount of code is totally redundant without the data! I suppose you have NAs in the object cellpredweighted1 and by default sum() propagates NAs to the answer because if one or more elements of a vector is NA then by definition the summation of those elements is also NA.
If the above is the case here, then simply adding na.rm = TRUE to the tapply() call should solve the problem.
tapply(cellpredweighted1, Census$municode, sum, na.rm = TRUE)
You should be asking yourself why there are NAs at this stage and if these result from errors earlier on the process.