# DatMA: Database of students' program choice for frame A In Frames2: Estimation in Dual Frame Surveys

## Description

This dataset contains some variables regarding the program choice for a sample of 180 students included in the sampling frame A.

## Usage

 `1` ```DatMA ```

## Format

Id_Pop

An integer from 1 to N, with N the number of students in the whole population, identifying the student within the population.

Id_Frame

An integer from 1 to N_A, with N_A the number of students in the frame, identifying the student within the frame.

Prog

A factor with three categories (academic, general and vocation) indicating the program choice of the student.

Ses

An ordinal factor with three categories (low, middle and high) indicating the socio-economical status of the student.

A number indicating the mark of the student in a reading test.

Write

A number indicating the mark of the student in a writing test.

Sch_Size

A number indicating the size of the school the students belongs to.

Domain

A string indicating the domain each student belongs to. Possible values are "a" if student belongs to domain a or "ab" if student belongs to overlap domain.

ProbA

First order inclusion probability in frame A.

ProbB

First order inclusion probability in frame B. This probability is 0 for students included in domain a.

## Details

The sample, of size n_A = 180, has been drawn from a population of N_A = 5500 students according to a proportional-to-size sampling desing according to the size of the school. So, students attending bigger schools have a higher probability of being selected in the sample. N_{ab} = 2000 of the students composing the population belongs also to frame B.

`DatPopM`
 ```1 2 3 4 5 6 7``` ```data(DatMA) attach(DatMA) #Let perform a brief descriptive analysis for the main variable summary (Prog) #And let do the same for the numerical auxiliary variables Read and Write summary(Read) summary(Write) ```