Journey with Udacity Data Science Challenge Scholarship 2018/2019 powered by Bertelsmann — — Blog 1
Question 1: What information would help people to trust the result of a survey？
- How many people will be surveyed
- Who will be surveyed
- How the survey was conducted
Question 2: How to define and measure Constructs?
Definition: A construct is anything that is difficult to measure because it can be defined and measured in many different ways.
Examples: happiness, memory, guilt, love, hunger
Measure Methods: There are lots of ways to measure that, and many have their special measure methods
Operational definition: The operational definition of a construct is the unit of measurement we are using for the construct. Once we operationally define something it is no longer a construct.
Examples: ‘age in years’ is her operational definition of ‘age’.
Question 3: What concepts do you need to know about Data?
Population: The population is all the individuals in a group.
Sample: The sample is some of the individuals in a group. Most of times the population is so big so we need the sample.
Parameters/Statistic: A parameter defines a characteristic of the population whereas a statistic defines a characteristic of the sample.
Example: The mean of a population is defined with the symbol µ whereas the mean of a sample is defined as X-bar
Randomness: Every one has equal chance to be choose.
Question 4: How we figure out the relationships between variables?
There is a very important theory named Golden Arches Theory of Conflict Prevention from Thomas Friedman: No two countries with a McDonald’s have ever gone to war since opening the McDonald’s.
Is that really TRUE?
Of course not！！！
We must be aware that correlation does not imply causation. We may ignore possible lurking variables. If we just want to show relationships between the variables, we can do observational studies or surveys.
Observational Study: An observational study is when an experimenter watches a group of subjects and does not introduce a treatment.
Treatment: In an experiment, the manner in which researchers handle subjects is called a treatment. Researchers are specifically interested in how different treatments might yield differing results.
But if we want know the causation, we must do controlled experiment.
Questions 5: What is basic concept about the controlled experiment?
Firstly there are two different types of variables.
Independent Variable: The independent variable of a study is the variable that experimenters choose to manipulate. It is usually plotted along the x-axis of a graph.
Dependent Variable: The dependent variable of a study is the variable that experimenters choose to measure during an experiment. It is usually plotted along the y-axis of a graph.
Treatment Group: The group of a study that receives varying levels of the independent variable. These groups are used to measure the effect of a treatment.
Control Group: The group of a study that receives no treatment. This group is used as a baseline when comparing treatment groups.
Blinding: Blinding is a technique used to reduce bias. Double blinding ensures that both those administering treatments and those receiving treatments do not know who is receiving which treatment.
I am just new to data science . Any advises to my blog are welcome! Feel free to contact me if you have any problem or doubts about the content.
