R语言人口调查数据分析英文案例 附代码数据

An exploration of the

BRFSS data

Fernando Montenegro -

fsmontenegro@

Executive Summary

This document is the report from the final course project for the

Introduction to Probability and Data

course, as part of the

Duke/Coursera

Statistics with R

specialization. The project

consisted of exploring a real-world dataset -

CDC’s 2013

Behavioral Risk Factor Surveillance System

- and creating a report

on three student-chosen research questions.

The research questions chosen - and their respective results -

were:

?

Is a respondent’s opinion of their health status related to their

Body Mass Index (BMI)? Is there any difference between

gender?

?

Yes, there were noticeable relations between health

perception and BMI, as well as gender-specific

differences.

?

How does being a parent of a young child affect the amount sleep

time reported? How is this reported differently between

genders?

?

Being a parent of a young child resulted in less sleep being

reported, including a difference between the genders.

?

Are responses to general health perception related to the time of

year of the survey was conducted? How do any differences

show up across states?

?

There were no significant differences between winter and

non-winter responses at the national level, but there

indications of differences in per-state responses.

Setup

The initial phase consisted of loading the required packages and

data. This was done as per the project instructions.

Load packages

library

(ggplot2)

library

(dplyr)

Load data

The data was loaded from a local copy of the file, as per course

instructions.

load

(

)

dim

(brfss2013)

## [1] 491775 330

As can be seen above, the dataset consisted of almost 500,000

observations with 330 possible variables. Not all observations

included all variables, so data quality was handled individually on

each question below.

Part 1: Data

Background on the BRFSS

According to the CDC

website

, “The Behavioral Risk Factor

Surveillance System (BRFSS) is the nation’s

premier system of

health-related telephone surveys that collect state data about U.S.

residents regarding their health-related risk behaviors, chronic

health conditions, and use of preventive services. Established in

1984 with 15 states, BRFSS now collects data in all 50 states as

well as the District of Columbia and three U.S. territories. BRFSS

completes more than 400,000 adult interviews each year, making it

the largest continuously conducted health survey system in the

world.”

Methodology

According to

the CDC, “BRFSS is a cross

-sectional telephone

survey that state health departments conduct monthly over landline

telephones and cellular telephones with a standardized

questionnaire and technical and methodological assistance from

CDC. In conducting the BRFSS landline telephone survey,

interviewers collect data from a randomly selected adult in a

household. In conducting the cellular telephone version of the

BRFSS questionnaire, interviewers collect data from an adult who

participates by using a cellular telephone and resides in a private

residence or college housing.”

Observations on Generalizability,

Causality, and Bias

While the course material makes brief references to more

advanced statistical content (causal inference), given the author’s

current knowledge about causality, the following statements can be

made:

?

On the topic of Generalizability: given the breadth of the survey -

across all 50 states and other US territories, coordinated by

the CDC with each state’s health agency, …

- it does seem to

capture enough of a random sample to make it generalizable

to the broad US population.

?

On Causality: given that the BRFSS is an observational exercise -

with no explicit random assignments to treatments - all

relationships indicated may indication association, but not

causation.