Health Data and Studies
What is data? How do we collect it? Who participates in a study?
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�Health Data and Studies
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Module 2:
Learning Objectives:
What are some key terms?
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Terms to know
A collection of information, such as measurements, observations, or descriptions of things.
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Terms to know
Definition: Data
Science is about measuring relationships between two or more variables.
A variable is anything that can be measured in a research study.
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Terms to know
Definition: Variable
A general pattern or direction in which something is developing or changing
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We can examine the trend of variables over time.
Let’s look at some examples...
Terms to know
Definition: Trend
As ice cream sales go up, so do shark attacks...
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Looking at trends
Does this mean that buying ice cream causes shark attacks?
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Looking at trends
Or… does this mean that shark attacks cause people to buy more ice cream?
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Looking at trends
What could be going on here?
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Looking at trends
Both events happen in the summer!
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Looking at trends
Definition: Correlation is when two events are related, but one does not necessarily cause the other
Definition: Causation is when one events causes the other to occur
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Correlation vs. Causation
Positive Correlation
Both trends move in the same direction!
As one trend goes up, the other trend goes up
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Correlation vs. Causation
Negative Correlation
The trends go in opposite directions!
As one trend goes up, the other trend goes down
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Correlation vs. Causation
No Correlation
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Correlation vs. Causation
Try describing a relationship....
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Vivek notices that students in his class with larger shoe sizes tend to have higher grade point averages. Based on this observation, what is the best description of the relationship between shoe size and grade point average?
Choose 1 answer:
Check your knowledge
Try describing a relationship....
Vivek notices that students in his class with larger shoe sizes tend to have higher grade point averages. Based on this observation, what is the best description of the relationship between shoe size and grade point average?
Choose 1 answer:
Check your knowledge
How do we collect data?
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To understand trends, we need to look at data over time among the same people
Longitudinal - Across time
Longitudinal Cohort Study
Cohort - Group of people
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How do we collect data?
How do we decide who should be in a research study?
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How do we collect data?
Population versus Sample
Definition: Population
A population contains all members of a specified group.
Definition: Study Sample
A sample contains a part, or a subset, of a population. The size of a sample is always less than the size of the population from which it is taken.
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Data collection
Which people would you invite?
For example, if you want to know the most popular activities to do in Los Angeles, which people would you survey?
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Data collection
Definition: Sampling Bias
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Sampling bias happens if there are more survey responses from certain groups than others or if results favor one outcome over another.
Data collection
Population
Sample
Democrats
Republicans
How many people would you invite into your study?
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Data collection
Now let’s look at a real longitudinal cohort study!
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Monitoring the Future Study
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Monitoring the Future
Survey-data has been used to tell stories that make real differences and shape policies that protect youth and benefit communities!
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Monitoring the Future
How do we present data?
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X-AXIS
Y-AXIS
Monitoring the Future
Next Up: Monitoring
the Future Activity�
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Activity 2.1