JA3. Regression¶
Statement¶
Your learning journal entry must be a reflective statement that considers the following questions:
1. Describe what you did¶
This was the third week of this course, it was about regression. I started the week as usual by trying the self-quiz then I watched the lecture videos and started to read the text; the text size for this week was reasonable and I was able to finish it. Later, I did the programming assignment and the graded quiz which helped me a lot on applying what I learned; and finally I am preparing the learning journal.
2. Describe your reactions to what you did¶
The idea of regression was understandable, as we worked a lot with statistics in previous courses, and being able to extend sample observations to predict values outside of the sample is a very useful tool.
3. Describe any feedback you received or any specific interactions you had. Discuss how they were helpful¶
I did not receive any feedback that is worth mentioning.
4. Describe your feelings and attitudes¶
The topic was interesting, but the details showed how easy it is to miss interpret the results of a regression model and to falsely claim (or assume) that there is a relation between the dependent and some independent variables, to later discover that the relation is not significant. The issue here is that the model is not wrong and can not tell you that things are wrong; instead, it is up to the analyst’s experience to spot such issues and decide the appropriate action.
5. Describe what you learned¶
We learned about linear regression, simple linear regression, residual, residual sum of squares (RSS), least squares, population regression line, multiple linear regression, and potential problems with regression.
The discussion assignment asked us to elaborate more on the limitations of regression, which included the false assumption of linearity, the correlation of error terms, the non-constant variance of error terms, outliers, high-leverage points, and collinearity.
The programming assignment included two practical exercises that we were supposed to solve using R, the first one was about simple linear regression and the second one was about multiple linear regression and was fun to play with.
6. What surprised me or caused me to wonder?¶
I was surprised how complex the formulas were to calculate the regression coefficients, especially with different parameters, and how to asses the model predictions and then it was very easy calculating such things in R. You do not even need to pass any arguments to any function, you just pass the model itself to the coef or confint functions and they will do the rest. Also the summary() function was able to print some useful information about the model straight away.
7. What happened that felt particularly challenging? Why was it challenging to me?¶
Interpreting the plots and extracting useful information out of them was hard to try, I had to stand in front of plots for a long time trying to decode what the text is mentioning about the plot and how to verify their extracted information.
8. What skills and knowledge do I recognize that I am gaining?¶
Learning R and how to do day-to-day tasks with it, and how to use it to solve problems along with using it according to the course requirements is a very useful skill that I am gaining.
9. What am I realizing about myself as a learner?¶
I realized that it is hard for me to grasp complex formulas, so I ended up ignoring them all, let alone memorizing them; luckily, R itself or other community libraries provides useful methods that can be used to calculate such formulas with ease.
10. In what ways am I able to apply the ideas and concepts gained to my own experience?¶
I would like to use R to compute some statistics about the data that I am working with, and I would like to use it to create some plots that can help me spot some patterns and convince my work colleagues about some of my findings.
11. Describe one important thing that you are thinking about in relation to the activity¶
Building models is very complex and with the lots of required steps, it is easy to step on wrong feet. I’m thinking of there is ways to warn users about such bug in models as soon as possible.