Sleep Matters 😴

Survey Design and Statistical Analysis , April 2018

Collaborators:

contributions welcome

  • This survey was created using Google Forms and can be found here.

  • Final Report in md version, please click here

The Question

The survey question is “How does sleeping duration affect student’s MDS performance (grade)?”

  • We believe sleep has a significant effect on students’ grades. Therefore, we would like to test our hypothesis by conducting a survey in which we will ask several questions to find out the validity of our belief.

Survey Analysis

We collected data into the following survey via Google Survey Tool. survey questions and survey data is accessible on following links.

We applied Ordinal Regression analysis onto our survey outcome which can be found on final report.

Results and Conclusion

Survey data for each analysis variable

Correlation plot of each variable

  • For categorical variables, the concept of correlation can be understood in terms of significance test and effect size (strength of association).
  • The measure of association indicates the strength of the relationship, whether, weak or strong but it does not indicate causality.

  • Exercise has a weak negative correlation with stress and commute_time with correlation coefficient rho as -0.3.
  • Grades have weak negative correlation with stress with rho as -0.3.
  • Another interesting observation we found was stress and going out and exercise are negatively correlated with rho as -0.5.

Model Selection

  • Since our response variable grade is an ordinal variable, we choose the cumulative link models (CLMs) to fit our data.

Significance testing and results

  • In summary, sleeping for 6 - 7 hours, instead of less than 5 hours, will increase the log odds of getting a better grade; sleep for 8 - 9 hours, instead of 6 - 7 hours, will decrease the log odds of getting a better grade.

  • Therefore, 6 - 7 hours seems the best sleep duration for a better grade. Too little sleep may affect the efficiency of study, and too much sleep will take away the study time.

Running the Analysis

Clone the repo for your survey that using the instruction in:

Project Repo