Variables

Measured/ manipulated or both

100

hair colour

       

 

both

200

Cell phone use 

Both

300

extraversion

Measured

400

your reading ability

measured

500

attend public or private school

measured/ both

Name the Variable

100

What type of variable would separate answers into A, B, C, D (AKA multiple choice exams) 

Nominal - they are a categorical variable where the letter has no meaning to order 

200

Movies from most to least favourite 

This represents an Ordinal scale because they are ordered from "best" to "worst" in terms of ranking. Interval is not known in an ordinal variable - meaning that from the best movie to the worst movie there are not exactly 9 points separating them 

300

What type of variable is height or weight and why? 

Ratio Scale - both weight and height are a continuous variable, yet they have a true variable (meaning the absence of something) in this case zero kg means zero weight and zero cm means zero height. 

400

Number of exams questions answered correctly is a _____ type of variable 

Ratio - because there is an equal distance between 5 questions right and 10, and 20-30 correct answers and there is a true zero 

500

Name an interval variable that is NOT temperature 

- PH scales

- IQ scores (there is no true zero) and there is a meaningful difference 

Describe the graph

100

Describe as many characteristics of a pie chart

"slices of a whole" 

"visual proportions" 

used for categorical data 

downside: they can be misleading and misused - such that all the parts do not add up to 100 

200

Describe the bar graph 

- categorical and continuous variable on axis (ex. gender and memory score) 

- easy to read and look at/ understand 

300

Box Plot

Median - middle bar (Q2) 

first quartile (25th percentile) 

third quartile (75th percentile) 

IQR - Q3-Q1 

400

Histrogram

for continuous data 

starts with a frequency distribution 

No gaps 

500

Frequency Polygon

continuous data 

smooth curve 

uses midpoint - because this best represents the category

allows us to take scores that are in between

Name the real limit

100

103

(102.5-103.5)

200

63

(62.5-63.5)

300

15

(14.5-15.5)

400

24

(23.5-24.5)

500

212.5

212-213

shape of distributions

100

Multiple peaks 

Bi modal 

200

Skewed to the right --> 

Positive skew 

300

Skewed to the left 

negative skew (remember think negative numbers are to the left on the graph)

400

Why is a bell curve a normal distribution?

because all the scores are normally distributed (meaning half of the scores fall on either side of the midpoint) 

has a single peak (unimodal) 

two tails that extend equally 

forms a bell curve 

You will use this curve a lot this semester!!! 

500

Bonus point question! Can anyone describe what either positive kurtosis, or negative kurtosis

positive - leptokurtic (think more squished distribution) 

negative - platykurtic (think a plateau)