Psychology and Scientific Inquiry Unit 1 Psychology and Scientific Inquiry Day 4: Understanding and Interpreting Results Because if there’s no evidence, it didn’t happen! (like Russians rigging an election)

Objectives Terms: Identify methods of measurement Mean Understand the difference between correlation and causation Median Mode Range Correlation Correlation Coefficient Causation Logical Fallacy Placebo

Remind Me… What are the steps of Scientific Inquiry in Psychology? What is the LAST step? (And what does it mean?) What are the variables? What do the Independent and Dependent give us? Today we look at how we interpret results, but the biggest caution is that we understand what we are looking at, and what is REALLY measures…

Measuring Data Mean Median Mode Range The tools we use to look at data (things that can actually be measured) will look at lot like something from Math class Which is why CPT Curtis hates it So let’s see what those are and if we already understand them Mean Median Mode Range Math makes me sleepy

Measuring Data MEAN The Average of a group of data Let’s look at an example: 13, 18, 13, 14, 13, 16, 14, 21, 13 What’s the “average”? To remind us, that means add up the total and divide by the number of things Average or “Mean” = 15

Measuring Data MEDIAN The Middle Value (number in the middle) Let’s look at our example: 13, 18, 13, 14, 13, 16, 14, 21, 13 What’s the “middle”? We have to arrange the nine numbers. Which one is the “fifth” number? Median = 14

Measuring Data MODE The Number (or answer) Most Repeated Let’s look at our example: 13, 18, 13, 14, 13, 16, 14, 21, 13 Which numbers appears most? Keep in mind this is something we can use even if it’s not numbers, but answers Mode = 13

Measuring Data RANGE Difference between largest and smallest answer Let’s look at our example: 13, 18, 13, 14, 13, 16, 14, 21, 13 What’s the range? Subtracting 13 from 21… Range = 8… although some say 9…

Measuring Data So… what’s the point and why do these matter? In our example, there wasn’t a huge difference or “range”, nor were the Mode, Median, and Mean that different. BUT what if….

Income per family in thousands of Dollars Range Income per family in thousands of Dollars

So what’s the point? Depending on if we use Mean, Median, Mode, or Range, it will show different things. Also, it might be very misleading. Now let’s look at variables… What do THEY tell us?

Measuring Variables Correlation Correlation Coefficient For example… When one trait or behavior accompanies another There IS a relationship! (and maybe it’s complicated) Correlation Coefficient - The measurement of that relationship - Can be positive OR negative For example…

Does this mean that increased temperatures cause Cadets to sleep? Couldn’t it also mean that the greater the number of sleeping Cadets, the hotter the room? HOW CAN YOU TELL? Regardless, there is definitely a correlation

Measuring Variables A caution about Correlation Correlation is NOT Causation! Causation Changes in one variable directly cause changes in the other Let’s look at another example…

So… hotter temperatures kill Pirates?

Measuring Variables So do hotter temperatures mean less pirates? NO! Obviously there are other variables… But is there a correlation? Perhaps… but if we confuse it with causation Logical Fallacy - A flaw in reasoning - Assuming there is a relationship, or causation, or correlation when there is not

And finally… One extra little term you need to be familiar with, because it can often help us know if there is a REAL relationship between two variables… Placebo - Something given to a subject that has no physical effect, though the subject thinks it does Like giving a sugar pill instead of meds

So… What is the difference between causation and correlation? Why is that important? Keep that in mind when reading Psychological Studies Next Week –Study Guide (You will work on and complete in class) March 1st – TEST (Scientific Inquiry and Psychology)

Objectives Terms: Identify methods of measurement Mean Understand the difference between correlation and causation Median Mode Range Correlation Correlation Coefficient Causation Logical Fallacy Placebo