BASIC CONCEPTS Flashcards

Question

What is the difference between qualitative and quantitative variables?

Answer 1

Quantitative variables have values that are numbers. Qualitative variables have values that are qualities or categories.

Answer 2

Nominal and ordinal. Nominal: - categorical (e.g. sex, marital status...) - the one we use the most Ordinal: - it's rank / order (pain level 6 is greater than pain level 3) - there is a magnitude (e.g. pain rating, stages of cancer...) - no equal interval. The difference doesn't have the same meaning; the difference between pain level 4 and 5 and pain level 2 and 3 is not the same. - greater than and less than relationships. example - running competition: Gold > Silver > Bronze Between Gold and Silver 2 seconds, but between Silver and Bronze, 10 seconds.

Answer 3

Interval and ratio. Interval: - equal intervals - Magnitude - origin is arbitrary (e.g. temperature, 0 Celsius doesn't mean absence of heat, and compared to Kelvins, you can't say twice as much or wtv...) -greater than and less than relationships. Proof: At 25°C, it’s 298.15 K At 50°C, it’s 323.15 K Ratio: - equal intervals - magnitude -greater than and less than relationships. - fixed origin (length, mass, reaction time...): * The only time you can say twice as so and so... *

Answer 4

Physical (i.e. reaction time) and non-physical variables (i.e. mood)

Answer 5

A construct is a variable that is not DIRECTLY (keyword) measurable. For example, intelligence, memory, anxiety, mood, depression, stress.

Answer 6

1. Operationally define specific variables used to measure this construct * An essential component of an operational definition is measurement (operational measure) 2. We create a tool (i.e. questionnaire) that allows us to operationally measure (assign numbers to) a variable we are interested in. * These numbers provide the raw data for our stats analysis Go see examples diapo (dictionary def of a construct vs. operational definition)

Answer 7

Construct: This is the abstract idea or concept you're trying to study. It's something broad and not directly measurable, like stress, intelligence, or happiness. Variable: This is something measurable that you use to represent the construct. A variable is a specific aspect or indicator of the construct that can be measured. So, while the construct is the big idea (like stress), the variable is a specific way you decide to measure that idea. Construct: Stress Variable: Anxiety level, heart rate, or self-reported feelings of being overwhelmed

Answer 8

1. Reliability: The operational measure has to be stable, peu importe le nombre de fois que telle personne est testée - should give same/similar result. 2. Validity: "Does that mood test really measure mood"

Answer 9

No, no matter how reliable and valid the operational measure is. All measurement is subject to some measurement error.

Answer 10

Obtained Score = “True Score” + Random Error Obtained Score: The score you actually measure (e.g., the score someone gets on a test). True Score: The "real" score that reflects a person's actual ability or characteristic, free from any measurement errors. Random Error: The unpredictable fluctuations that cause the obtained score to deviate from the true score (e.g., distractions, fatigue, or guesswork).

Answer 11

1. Usually more practical (difficult to manage, costly...) 2. GOAL OF SCIENCE is to make generalizations about events beyond our reach. (in order to estimate the population parameter).

Answer 12

study a group of individuals who are believed to be representative of the general population (or some particular population of interest). Trying to minimize systematic differences between sample and population.

Answer 13

The researcher obtains a complete list of all the members of the population and randomly selects some number of them to study. Examples: 1) telephone survey 2) putting all the names on slips of paper and drawing them from a hat

Answer 14

Selecting whomever is available without any systematic plan. This is likely to result in a sampling bias (biased sample). examples: 1) surveying each person you run into on the street 2) selecting students who sit in the front row Let’s say you want to study the study habits of college students to understand how they prepare for exams. Instead of selecting a representative group of students from different universities, majors, and backgrounds, you decide to survey only your friends in your psychology class. These friends are easy to reach and accessible, so you choose them for your study.

Answer 15

In psychology research, achieving true random sampling—where every single member of the population has an equal chance of being selected—is often difficult or impossible (access issues...). However, they still try to aim for a representative sample.

Answer 16

Because parameter estimates are much more accurate is samples are representative of population. And for samples to be representative of populations, all members should have an equal chance of being selected.

Answer 17

Difference between the statistic computed from the sample and the parameter computed from the population.

Answer 18

By making sure the sample is representative to the population. How? 1) big sample size 2) random sampling (everyone had an equal chance of being selected)

Answer 19

N = # of scores in the population n = # of scores in the sample

Answer 20

"X" or "Y" stands for the variable measured. It's the "i"th score, where "i" can vary from 1 to N. Score 1, 2......