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C.Chapter1Salkind_Acc.pptxChapter One (Salkind)
Statistics of Sadistics?
Welcome to your first official chapter in Research Methods and Design I. Are you excited to talk about statistics?
No? Not even a little?
Too bad, because here we go!
Welcome!
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An Overview of This Chapter
In this chapter we cover the following items …
Part One: Why Statistics?
Part Two: A 5-Minute History of Statistics
Part Three: Statistics: What It Is (And Isn’t)
Part Four: What Am I Doing In A Statistics Class?
Part Five: An Eye Toward The Future
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Part One
Why Statistics?
Why Statistics?
There may be dozens of reasons why statistics makes you groan:
I don’t understand math.
Statistics are tough.
Why do I even need this statistics stuff?
Why can’t I just let a computer do statistics for me?
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Why Statistics (2)?
There may be more reasons you’re apprehensive:
I don’t plan on doing research when I graduate, so learning statistics is waste of time.
The minute I leave class, I won’t remember any of this stuff.
Those odd Greek symbols ( µ σ ) make no sense!
And a few other biggies …
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What am I supposed to do with a formula as complex as this?
Wow!
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Although you might have some trepidation about statistics and their applications, this course is designed to help you see past your fears, skepticism, and anxiousness about statistics
I know statistics may scare a lot of you, but I think that is mostly because you don’t have the foundation yet to understand when, how, and why you should use statistics.
But don’t let fear of the unknown prevent you from getting that knowledge. In a month, you might actually think methods is fun!
Don’t be scared!
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Part Two
A 5-Minute History Of Statistics
A 5-Minute History of Statistics
Imagine a caveman looking for food. He comes across a huge herd of bison, and he knows he can kill them all now OR come back time and time again. What does he do? What information does he use to make his decision about how many to kill and eat?
If you said counting, you’re absolutely correct! Why deplete the food source if you only need a few bison at a time to live? Why not take only what you need and come back for more later?
As our earliest ancestors came to know, counting is not only a good idea, it is a useful skill
A 5-Minute History of Statistics (2)
We have come a long way from counting bison, as has our skills in trying to predict today what we hope to find tomorrow.
A great deal of statistics compares our expectations with reality. If I expect XYZ to occur, will it? If it does occur, how confident can I be that I understand WHY it occurred.
You’ll learn about a wide variety of statistics in this course, with some stats based on correlations (a relationship among variables) and some based on causation (A leads to B).
In correlational research, there is a relationship between two variables. That is, variables A and B are linked somehow
When variable A increases, B also increases
The more I like the color green, the more I’ll tend to buy green clothes
Correlational Research
Or it could be that as A increases, B decreases
As I watch more TV, my grades decrease
More examples of correlations
Early Correlational Research
Some of the first “statistics” come from this correlation domain. Francis Galton, for example, studied intelligence by looking at the similarity of intelligence among members of the same family
He used a correlation coefficient technique to assess this relationship (we’ll get to those in Chapter 5 - Salkind!)
Other early researchers looked at statistics in agricultural areas, astronomy, or politics. While such group statistics are common, other early researchers focused on single cases …
Single Case Experimental Designs
When it comes to human behavior, many early psychological researchers focused on single-case experimental designs
As far back as 1860, Gustav Fechner explored human sensory processes by developing the concepts of sensory thresholds and just noticeable differences
Imagine a regular staple (unstapled!). It has two prongs, right? Now, if you pressed the two prongs of this staple into your skin, would you feel two prongs or just one?
Research by Fechner and others shows that we have different sensory thresholds for different body parts
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Fechner’s Single Case Design
That is, the receptors in our skin are NOT distributed in a uniform way in our bodies.
Some areas—such as our fingers and lips—have more touch receptors than other areas, such as our backs. That's one reason why we are more sensitive to touch in our fingers and face than on our backs. We can feel both staple prongs easier on our faces than on our backs!
| Site | Threshold Distance |
| Fingers | 2-3 mm |
| Upper Lip | 5 mm |
| Cheek | 6 mm |
| Nose | 7 mm |
| Palm | 10 mm |
| Forehead | 15 mm |
| Foot | 20 mm |
| Site | Threshold Distance |
| Belly | 30 mm |
| Forearm | 35 mm |
| Upper arm | 39 mm |
| Back | 39 mm |
| Shoulder | 41 mm |
| Thigh | 42 mm |
| Calf | 45 mm |
How Far Do Prongs Need To Be Apart Before We Can Detect Two Prongs?
Other Single Case Design Examples
Think about some other early single-case experimenters …
Herman Ebbinghaus: Focused on verbal learning and memory, often testing himself with “nonsense” syllables
He’d memorize list of syllables, like “FHS” and “UDP” and then quiz himself on these lists
More Single Case Design Examples
John Watson looked at fear responses in “Little Albert”. Do you know about this infant, Little Albert? Watson presented Albert with a white rat, which Albert loved. Then Watson clanged a hammer into a metal pole, scaring the baby in the presence of the rat. Soon, Albert paired the loud noise with the presence of the rat, and Albert developed a rat phobia.
The list of single-case experiments goes on, of course, but our statistical understanding in psychology leapt forward with the advent of complex techniques like the t-Test and ANOVA
Experimental Procedures
Experimental Procedures
Statisticians like Ronald Fisher developed powerful statistics in the early 1920s to better understand the relationships among variables and between groups
Today, statistics are easier to run and understand given the technological tools at our disposal (like SPSS on computers!)
But just because we have tools that run statistics fast doesn’t mean we should neglect our understanding of those statistics
Standardization
The good thing to know (especially in this course) is that the statistical tests we use (and the reasons behind why and when we use them) have a degree of standardization.
Standardization (2)
Such standardization lets us use the same kind of analyses across a wide variety of studies, providing us with a common language about results. It also gives us the ability to compare one study to another
This class will each you that common language!
But for now, a quick pop quiz question (quiz yourself) …
One of the most used statistical programs that has opened up the use of sophisticated techniques to those who want to engage in research is:
A). SPSS
B). Microsoft Word
C). Mini Tab
D). None of the above
Pop Quiz 1: Quiz Yourself
Next semester, you’ll actually use SPSS yourself in Methods Two! Something to look forward to, right!
One of the most used statistical programs that has opened up the use of sophisticated techniques to those who want to engage in research is:
A). SPSS (correct answer)
B). Microsoft Word
C). Mini Tab
D). None of the above
Answer 1: A
Part Three
Statistics: What It Is (And Isn’t)
What are statistics?
Statistics describe a set of tools and techniques used for describing, organizing, and interpreting information or data
Data might involve scores on a test, speed with which problems are solved, the number of complaints that get called in to an Apple center’s help line when the newest iPhone goes berserk, etc.
In this course, we will concentrate on two primary statistics:
1. Descriptive Statistics
2. Inferential Statistics
Descriptive Statistics
Descriptive statistics are used to organize and describe the characteristics of a collection of data (a data set or just data)
In your introductory statistics class, you probably came across a few of these “descriptive” statistics, including:
A. The Mode
B. The Median
C. The Mean
D. The Standard Deviation
The Mode
A. The mode is simply the most frequently occurring response in a data set. Below, which is the most frequently occurring food (the most preferred food)? We’ll try a pop quiz! …
| Name | Age | Preferred Food | Living Situation |
| Jill | 17 | Italian | Off-campus |
| Alfred | 18 | Salads | Off-Camps |
| Gary | 18 | Mexican | Off-Campus |
| Beth | 20 | Chinese | On-Campus |
| Ross | 19 | Italian | Off-Campus |
| Amanda | 21 | Thai | On-Campus |
| Stephanie | 22 | German | Off-Campus |
What’s the mode for food?
A). Italian
B). Chinese
C). Thai
D). Salad
E). German
| Preferred Food |
| Italian |
| Salads |
| Mexican |
| Chinese |
| Italian |
| Thai |
| German |
Pop Quiz 3: Quiz Yourself
What’s the mode for food?
A). Italian (correct answer)
B). Chinese
C). Thai
D). Salad
E). German
| Preferred Food |
| Italian |
| Salads |
| Mexican |
| Chinese |
| Italian |
| Thai |
| German |
Italian occurs twice here. All others only occur once. So Italian is the mode (most frequent)!
Answer 3: A
The Median
B. The median is the middle number in a distribution. Think about the following data set. If you ranked ages from low to high, which one falls in the middle?
| Name | Age | Preferred Food | Living Situation |
| Jill | 17 | Italian | Off-campus |
| Alfred | 18 | Salads | Off-Camps |
| Gary | 18 | Mexican | Off-Campus |
| Beth | 20 | Chinese | On-Campus |
| Ross | 19 | Italian | Off-Campus |
| Amanda | 21 | Thai | On-Campus |
| Stephanie | 22 | German | Off-Campus |
Statistics: What It Is (And Isn’t)
Here are the ages listed from low to high
| Name | Age | Preferred Food | Living Situation |
| Jill | 17 | Italian | Off-campus |
| Alfred | 18 | Salads | Off-Camps |
| Gary | 18 | Mexican | Off-Campus |
| Ross | 19 | Italian | Off-Campus |
| Beth | 20 | Chinese | On-Campus |
| Amanda | 21 | Thai | On-Campus |
| Stephanie | 22 | German | Off-Campus |
What’s the median for age?
A). 17
B). 18
C). 19
D). 20
E). 21
| Age |
| 17 |
| 18 |
| 18 |
| 19 |
| 20 |
| 21 |
| 22 |
Pop Quiz 2: Quiz Yourself
What’s the median for age?
A). 17
B). 18
C). 19 (correct answer)
D). 20
E). 21
| Age |
| 17 |
| 18 |
| 18 |
| 19 |
| 20 |
| 21 |
| 22 |
Answer 2: C
More Median Examples
Which preferred food is the median?
| Name | Age | Preferred Food | Living Situation |
| Jill | 17 | Italian | Off-campus |
| Alfred | 18 | Salads | Off-Camps |
| Gary | 18 | Mexican | Off-Campus |
| Ross | 19 | Italian | Off-Campus |
| Beth | 20 | Chinese | On-Campus |
| Amanda | 21 | Thai | On-Campus |
| Stephanie | 22 | German | Off-Campus |
Ha! Trick question. Food actually differs in terms of category, not ranking!
Imagine we somehow put food preference into “order” …
More Median Examples (2)
Let’s say we have this order
Is the median salad? Salad is in the middle, right?
Well, what if I alter the order …
| Preferred Food |
| Italian |
| Italian |
| Mexican |
| Salad |
| Chinese |
| Thai |
| German |
More Median Examples (3)
Is the median Chinese now?
It doesn’t make sense to use the median for categorical data like food preference. For categories, just use the mode (most frequently occurring)
| Preferred Food |
| Thai |
| Italian |
| Mexican |
| Chinese |
| German |
| Italian |
| Salad |
More Median Examples (4)
The Mean
C. The mean is simply the average number. In this case, we again only look at ranked data. What is the average age? Yup, another pop quiz …
| Name | Age | Preferred Food | Living Situation |
| Jill | 17 | Italian | Off-campus |
| Alfred | 18 | Salads | Off-Camps |
| Gary | 18 | Mexican | Off-Campus |
| Ross | 19 | Italian | Off-Campus |
| Beth | 20 | Chinese | On-Campus |
| Amanda | 21 | Thai | On-Campus |
| Stephanie | 22 | German | Off-Campus |
What’s the mean for age?
A). 17.21
B). 18.53
C). 19.29
D). 20.10
E). 21.12
| Age |
| 17 |
| 18 |
| 18 |
| 19 |
| 20 |
| 21 |
| 22 |
Pop Quiz 4: Quiz Yourself
What’s the mean for age?
A). 17.21
B). 18.53
C). 19.29 (correct answer)
D). 20.10
E). 21.12
Let’s see how this works …
Answer 4: C
Calculating the Mean
C. The mean is simply the average number. You add all the ages and divide by the total number of people in the dataset.
17 + 18 + 18 + 19 + 20 + 21 + 22 = 135 / 7 = 19.29 years
| Name | Age | Preferred Food | Living Situation |
| Jill | 17 | Italian | Off-campus |
| Alfred | 18 | Salads | Off-Camps |
| Gary | 18 | Mexican | Off-Campus |
| Ross | 19 | Italian | Off-Campus |
| Beth | 20 | Chinese | On-Campus |
| Amanda | 21 | Thai | On-Campus |
| Stephanie | 22 | German | Off-Campus |
More Mean Examples
What is the mean for preferred food?
| Name | Age | Preferred Food | Living Situation |
| Jill | 17 | Italian | Off-campus |
| Alfred | 18 | Salads | Off-Camps |
| Gary | 18 | Mexican | Off-Campus |
| Ross | 19 | Italian | Off-Campus |
| Beth | 20 | Chinese | On-Campus |
| Amanda | 21 | Thai | On-Campus |
| Stephanie | 22 | German | Off-Campus |
What is the Mean?
There is no “mean” food. What would that be? Italimexithaigermads? Make no sense!
| Name | Age | Preferred Food | Living Situation |
| Jill | 17 | Italian | Off-campus |
| Alfred | 18 | Salads | Off-Camps |
| Gary | 18 | Mexican | Off-Campus |
| Ross | 19 | Italian | Off-Campus |
| Beth | 20 | Chinese | On-Campus |
| Amanda | 21 | Thai | On-Campus |
| Stephanie | 22 | German | Off-Campus |
Standard Deviation
See, you’re a statistician already! Now for the hard one:
D. The standard deviation (SD), or the average amount of variation in a set of scores or the score’s deviation from the mean
Calculating the Standard Deviation
What is the SD for age?
Here’s your formula … Now solve!
| Name | Age | Preferred Food | Living Situation |
| Jill | 17 | Italian | Off-campus |
| Alfred | 18 | Salads | Off-Camps |
| Gary | 18 | Mexican | Off-Campus |
| Ross | 19 | Italian | Off-Campus |
| Beth | 20 | Chinese | On-Campus |
| Amanda | 21 | Thai | On-Campus |
| Stephanie | 22 | German | Off-Campus |
Just Kidding!
I’m just kidding. We’ll get to the standard deviation a bit later in the semester. All I want you to realize right now is that descriptive statistics simply describe the data set. You can contrast this with inferential statistics …
Inferential Statistics
Inferential statistics are used to make inferences (get it!) from a smaller group of data (a sample) to a larger one (a population)
Think about our class, which is a small sample of all psych majors at FIU. While I may want to know if the material that you see in this course helps you understand statistics, I may want to infer whether the course material would help other FIU psychology majors who are NOT currently taking stats.
That is, can I infer that YOUR performance would apply to the LARGER population of psychology majors at FIU?
What type of statistics is used to organize and describe the characteristics of a collection of data?
A). Inferential
B). Descriptive
C). Ordinal
D). Nominal
Pop Quiz 5: Quiz Yourself
What type of statistics is used to organize and describe the characteristics of a collection of data?
A). Inferential
B). Descriptive (correct answer)
C). Ordinal
D). Nominal
Answer 5: B
What am I doing in a statistics class?
We will learn a lot more about inferential statistics when we get to chapters 9, 10, 11, and 12 toward the end of the semester.
For now, let’s get back to the question we started this chapter with: What am I doing in a statistics class?
Part Four
What Am I Doing In A Statistics Class?
What Am I Doing In A Statistics Class
Probably the most common answer among psych students is, “It’s required for my major!” But statistics will help you in many other important ways
1. Taking this course shows your level of commitment to psychology
2. This course will give you an intellectual challenge in both writing about and engaging in psychological research
What Am I Doing In A Statistics Class (2)?
3. More importantly, understanding foundational concepts in research starting from the ground-up will help you as you move to higher level undergraduate courses
By the end of the two semester Research Methods and Design courses, you’ll have a better understanding of idea generation, study design, study implementation, data analysis, and publication
What Am I Doing In A Statistics Class (3)?
4. If you plan a career in any social, behavioral, or biological field, this course will give you the foundation many graduate programs expect of their incoming students
5. You can brag that you completed a tough course! (And it will be tough, but entirely doable. I think you’ll be surprised at just how much you will learn!)
6. Plus, it IS required, but I hope you like it anyway!
Part Five
An Eye Toward The Future
The next few classes…
Next class we are going to jump to a different book (Smith and Davis, The Psychologist as Detective), so make sure to read Chapter 5 in Smith and Davis: “Using The Scientific Method” or read the associated PowerPoint (the textbook is not required, the PowerPoints provided to you are sufficient).
