Research in Psychology and Basic Concepts in Statistics

Question 1

Entire collection of events/observations we are interested in studying

Answer 1

Population

Question 2

measurement taken from the population

Answer 2

parameter

Question 3

measurements collected from the sample drawn from the population

Answer 3

statistic

Question 4

denoted by the Greek letter (mu) µ.

Answer 4

population

*we must always clearly define the population we are
interested in.

Question 5

observations drawn from the population and used to infer something about the characteristics of the population

Answer 5

samples

Question 6

term used to refer to the population where samples are drawn from

Answer 6

sampling frame

Question 7

things/observations/constructs that can be measured, controlled, or manipulated in research and can take on different values

Answer 7

variable/s

Question 8

• variables that could have an effect on other variables and the one usually controlled in research
• may be either quantitative or qualitative and discrete or continuous

Answer 8

independent variable

Question 9

• variable affected by the variations in the independent variable
• generally, but not always, quantitative and continuous

Answer 9

dependent variable

Question 10

variables that can affect the outcome of the study, but which are not strictly part of the study

Answer 10

confounding variables

Question 11

variables that can take on only a limited number of values (e.g., gender, high school class)

Answer 11

discrete variables

Question 12

variables which can assume, at least in theory, any value between the lowest and highest points on the scale. (e.g., age and self esteem score)

Answer 12

continuous variables

Question 13

data which are results of any sort of measurement

Answer 13

quantitative data/measurement data

Question 14

frequency data or qualitative data

Answer 14

categorical data

Question 15

may have an infinite number of values between adjacent units on the scale, all measurements made are approximate

Answer 15

continuous variable

Question 15

____ are those values that are above and below the recorded value by one-half of the smallest measuring unit of the scale

Answer 15

real limits

Question 16

Levels of Measurement of Variables/Scales

variables that allow for only categorization into named sets. individual items belong to some distinctively different categories, but there is no quantifying or ranking of items

ex. male or female, republican, democrat, independent

Answer 16

nominal

Question 17

Levels of Measurement of Variables/Scales

variables which are ranked in order in terms of which has less and which has more of the quality represented by the variable, but not how much more

ex. socioeconomic status, military ranks, holmes and rahe (1967) scale of life stress

Answer 17

ordinal

Question 18

Levels of Measurement of Variables/Scales

not only give rank but also quantify and compare the size differences (interval) between

ex. temperature, fahrenheit and celcius

Answer 18

interval

Question 19

Levels of Measurement of Variables/Scales

variables that have an identifiable absolute of true zero point

ex. length, volume, time

Answer 19

ratio

Question 20

statistics primarily aimed at describing or summarizing data into meaningful framework

Ex: measures of central tendency (mean,
median, mode), measures of dispersion (standard
deviation, variance), graphical representations of data
or distribution (histograms, graphs, scatter plot etc.)

Answer 20

descriptive statistics

Question 21

(developed by John Tukey) - necessity of paying close attention to data and examining them in detail before invoking more technically involved procedures

Answer 21

Exploratory Data Analysis (EDA) or Exploratory Statistics

Question 22

inferring hypotheses or educated guesses from the sample to the population with the use of statistical procedures

Answer 22

inferential statistics

Question 23

Cornerstones of Research

measures what is supposed to be measured in research

Answer 23

validity

Question 24

Cornerstones of Research

replicability of findings in research

Answer 24

reliability

Question 25

Cornerstones of Research

refers to whether or not experimental or research results can be generalized to a real-world situation

Answer 25

external validity

Question 26

Cornerstones of Research

manipulation of variables in research has led to an observed/desired difference

Answer 26

internal validity

Question 27

Cornerstones of Research

a formal way of expressing a question as a prediction that can be tested

Answer 27

hypothesis

Question 28

Cornerstones of Research

hypothesis that states that there will be no effect of the independent variable on the dependent variable

Answer 28

null hypothesis

Question 29

__ or __ stands for the variable measured

Answer 29

X or Y

Question 30

___ stands for the total number of subjects or score

Answer 30

N

Question 31

___ is the ith score, where i can vary from 1 to N

Answer 31

Xi

Question 32

pronounced as X-bar

Answer 32

Mean

Question 33

Greek letter called “Sigma” or “summation of” or
“add up” or “take the sum of.

Answer 33

Σ

Question 34

therefore means “add up all the scores in X.

Answer 34

∑X

Question 35

sum of the squared scores

Answer 35

∑X²

Question 36

sum of the X scores, quantity squared.

Answer 36

(∑X)²