similar to: data frame to frequencies

I apologize up front if this has been covered elsewhere - but I can't find any such question. I have a data set that contains academic data: term (i.e., semester), student id, dept, class, success (1=Y, 0=N) I want to look at dept by term to determine descriptive statistics for success to failure ratios. The intent being to discover if there are departments that contribute significantly to

I have grades data. I read them from a csv in letter-grade format. I then converted them to levels levels(grades$grade)=c('A+','A','A-','B+','B','B-','C+','C','C-','D+','D','D-') And then to numbers grades$gp=grades$grade levels(grades$gp)=c(4.3,4.0,3.7, 3.3,3.0,2.7, 2.3,2.0,1.7, 1.3,1.0,0.7)

I have a form that I want to use to update multiple objects. In the controller, @grades = Grade.find(params[:grade].keys) @grades.each_with_index do |grade, i| grade.update_attribute(params[:grade][i]) end all_valid = @grades.inject(true) {|memo, c| c.valid? && memo } this doesn''t update the attributes as I would expect. (I would just use

I would like to create 15 box plots from two sets of data. Set1 - containts PayGrade, Min_Salary, Max_Salary data for 15 pay grades Set2 - contains PayGrade, Actual_Min, Actual_Max, and Actual_Mean for the 15 pay grades I would like 15 box plots (one for each paygrade) whose whiskers were the Min_Salary and Max_Salary data and whose ''box'' was Actual_Min, Actual_Mean,

I'm working on a quick tutorial for my students, and was planning on using Mann-Whitney U as one of the tests. I have the following (fake) data grade <- c("MVG", "VG", "VG", "G", "MVG", "G", "VG", "G", "VG") sex <- c( "male", "male", "female", "male",

Hi-- I am trying to normalize course grades for each instance of a course, e.g. Stats 1 Fall2009 J. Smith. I have a frame for all instances of a course, e.g. stats 1 in the last 5 years, that looks like SIDN TERM GRADE INST where SIDN is a Student ID Number, TERM is a factor that gives the quarter and year a course was offered, GRADE is a 0-4.3 grade and INST is the instructor, again as a

Dear R help gurus, I have the following problem and I would be delighted if you could help me. >From a large (1500) cohort of patients we have been taking some measurements (ECG measurements, but its not important). The measurements are ordinal in 4 grades (Grade I-IV, grade IV being the most severe form). Every patients has been measured several times (usually once per year). The

has_many :through is great. Is there anyway to find the association that it went through? Example: class Student has_many :projects has_many :grades, :through => :projects end student.grades[3].project Is it clear what I''m asking? How would this be done? -- Posted via http://www.ruby-forum.com/.

It seems that using a join model that joins with two has_many''s will fail to generate proper SQL class StudentSemesterRecord < ActiveRecord::Base belongs_to :semester has_many :discipline_records, :through => :semester end class Semester < ActiveRecord::Base has_many :student_semester_records has_many :discipline_records end class DisciplineRecord <

Read R-helpers, I'm relatively new to R and trying to jump in feet first. I've been able to learn a lot from on-line and printed documentation, but here's one question to which I can't find an answer. Well, it's a question with a couple parts. Thanks in advance for any direction (partial or complete) that anyone can provide. I have a data frame with three columns:

Hi All, I'm building an autograding framework for my biostatistics class this semester, and I am exploring different ways to automatically grade figures. In other classes, I teach ggplot2 and I extract information directly from the ggplot2 object. However, in this class we are using base R and I need to extract information from base-r graphics. I've tried several different approaches,

Env: R 2.8.1, Win Xp, Eclipse/StatET In a .Rd file, I have an example containing the lines: # calculate Y M, using polynomial contrasts trends <- as.matrix(VocabGrowth) %*% poly(8:11, degree=3) colnames(trends)<- c("Linear", "Quad", "Cubic") [At the risk of a long message, I'll append the complete .Rd file at the end of this message, in case this was

In a previous post, I mentioned a loop being used to generate graphs. I have some sample code partially put together but have found one offending line of code that I cannot figure out what to do with. I have one data frame called grade4. If I do something like hist(grade4$math) I get the appropriate chart. Within the loop, however, I am doing this for multiple files and grades, so I use

Dear List: I'm creating a series of barplots using Sweave that must assume a standard format. This is student achievement data and the x-axis must include all grades 3 to 8. In some cases, the data for a grade (or more than one grade) are missing in the vector math.bar, but are never missing for the vector apmxpmeet. The following sample code illustrates the issue. Using the code below to

I have data on every grade in all elementary schools in Chicago over 5 years. I would like to estimate a trend over time for each grade in each school. There are 17,600 data all together (about 460 schools, nearly 8 grades each, over 5 years). Is there a not-so-hard way to do this in R (I was thinking of using rlm)? ______________________________________________________________________ Stuart

Hello I have a longitudinal dataframe organized in the long format and would like to make comparison between successive rows if certain conditions apply. Specifically, I have four variables of interest: grade, score, year, and schid, associated with each school with 3 measurements per school per grade, therefore the rows are temporally ordered and each school occupies multiple rows. For example,

Hola, Esta pregunta la hice en stackoverflow <http://stackoverflow.com/questions/31137940/randomly-assign-teachers-to-classrooms-imposing-restrictions/31143808#31143808>pero nadie pudo contestarla. 1. Quiero generar N escuelas, con G grados y C divisiones. 2. Quiero asignar cada uno de T maestros a 2 divisiones en un grado y escuela Si tengo C=4 divisiones, puedo lograr lo que quiero con

Dear R-helpers, New to R, I'm in the middle of a project that I'm using to force me learn R. I'm running into some behavior that I don't understand, and I need some advice. In the last week I've gotten some great advice from the list on visualizing my data, and I was hoping people could help me get over another barrier I've encountered to my progress. Before I

I get the following error when I run qplot() qplot(grade, read,data = hhm.long.m, geom = c("point", "smooth")) Error in smooth.construct.cr.smooth.spec(object, data, knots) : x has insufficient unique values to support 10 knots: reduce k. I am not sure how to tackle this problem. When I take a subsample (< 1000) than I am able to run that function but with my sample

I have an app with the following models: course belongs_to :semester semester has_many: courses belongs_to :education education has_many :semesters In my old app (rails 1.2.6) I was able to access variables via controller @courses = Course.find(:all) view file: <% for course in @courses %> <%= course.name %> <- this line works <%= course.semester.name %> <- this is now