Week 2 Data Flashcards
Data
(What is Data)
Classification of Data
____ variable
(2 sub classification)
____ variable
(2 sub classification)
Practice problems:
GPA?
Score?
Happiness level on a scale from 1 to 7
Data
Collection of all variable measurements for the sample/individuals being studied.
Classification of data
Qualitative/categorical variables
Place an individual into one of several groups or categories.
Nominal: categories without order
Ordinal: categories with order
Quantitative/numerical variables
Take numerical values for which arithmetic operations such as adding and averaging make sense.
Discrete: counts; a number that only represents itself
Continuous: measures; the number represents a range of numbers (decimals)
Practice problems:
GPA is more categorical ordinal, but can be numerical discrete
Score is numerical discrete
Happiness level is categorical
Measurements
measurement system:____
validity:____
Reliability:____
measurement issues
Due to ____
Measurement bias/Response bias:
E.g. ____
Measurement error:
Measurement bias vs. measurement error:
____
Measurements
Measurement system: consists of a gauge (or device), method & operator.
Validity: measurement system measures what it intends to measure.
Reliability: consistency of measurement system.
Measurement Issues
Due to the device, method to operator.
Measurement bias (Response bias)
Predictable systematic difference (over/underestimate) between the measurements and the truth for the variables.
E.g. social desirability, fear of judgment, misunderstanding of the question, or other factors.
Measurement errors
Unpredictable differences between the measurements and truth for the variables.
Measurement bias vs measurement bias
Average all differences between the measurement and the truth.
if 0, measurement error.
If a fixed number, measurement bias.
Lecture check in quiz question 1
To investigate substance use patterns and trends in youth, the American Drug and Alcohol Survey is administered to Grades 4 to 12 students by trained interviewers in the students’ school settings. One of the questions asked by the interviewer is “Have you ever tried marijuana (pot, grass, hash, etc.)?”.
Based on the given information, which of the following biases or errors should the investigator anticipate?
Confounding
Selection bias
Response bias
Non-response bias
Measurement error
C
Response bias occurs when respondents provide inaccurate answers, either due to social desirability, fear of judgment, misunderstanding of the question, or other factors.
In this case, students might underreport or overreport their marijuana use because of concerns about confidentiality, fear of repercussions, or a desire to present themselves in a socially acceptable way.
Lecture check-in quiz problem 2
During winter, red foxes hunt small rodents by jumping into thick snow cover. Suppose foxes will continue their hunting and jump until they catch a small rodent. Researchers report that red fox hunting trips last, on average, 19 minutes and involve, on average, 7 jumps. In a surprising finding, they also report that 79% of successful jumps were made in the northeast direction. Which of the following statements about the variables upon which these results are based is TRUE?
The three variables are all quantitative.
The three variables are all categorical.
Two of variables are quantitative and one is categorical.
Two of the variables are categorical and one is quantitative.
C
Data is the collection of measurements of all individuals’ variable.
79% is the measurement, the variable is the jumps made in the northeast direction.
