Research design and appropriate analyses

Question 1

Define

Categorical variable

Answer 1

a variable that can take on one of a limited, and usually fixed, number of possible values, assigning each individual or other unit of observation to a particular group or nominal category on the basis of some qualitative property

Question 2

Define

Continuous variable

Answer 2

numeric variables that have an infinite number of values between any two values

Question 3

Define

Discrete variable

Answer 3

Variables that can only take on a finite number of values

Question 4

Define

Nominal variable

Answer 4

a variable that has two or more categories, but there is no intrinsic ordering to the categories

Question 5

Define

Null hypothesis

Answer 5

the hypothesis that there is no significant difference between specified populations, any observed difference being due to sampling or experimental error.

Question 6

Define

Ordinal variable

Answer 6

a scale that has the property of a nominal scale, but also identifies an ordering of objects in terms of the attribute

Question 7

Define

Parameter

Answer 7

a number that describe the data from a population

Question 8

Define

Probability Level (p-value)

Answer 8

A number calculated with statistical techniques that tells researchers how likely it is that the results of their experiment occurred by chance and not because of the independent variable or variables; the convention in science, including social psychology, is to consider results significant if the probability level is less than 5 in 100 that the results might be due to chance factors and noth the independent variables studied

Question 9

Define

Quantitative variable

Answer 9

Variables whose values result from counting or measuring something

Question 10

Define

Standard normal distribution

Answer 10

a normal distribution with a mean of zero and standard deviation of 1

Question 11

Define

Statistic

Answer 11

a number that describes the data from a sample

Question 12

Define

Z score

Answer 12

a linear transformation of test scores that expresses the distance of each score from the mean of the distribution of scores in units of the standard deviation of the distribution

Question 13

Definition

a variable that can take on one of a limited, and usually fixed, number of possible values, assigning each individual or other unit of observation to a particular group or nominal category on the basis of some qualitative property

Answer 13

Categorical variable

Question 14

Definition

numeric variables that have an infinite number of values between any two values

Answer 14

Continuous variable

Question 15

Definition

Variables that can only take on a finite number of values

Answer 15

Discrete variable

Question 16

Definition

a variable that has two or more categories, but there is no intrinsic ordering to the categories

Answer 16

Nominal variable

Question 17

Definition

the hypothesis that there is no significant difference between specified populations, any observed difference being due to sampling or experimental error.

Answer 17

Null hypothesis

Question 18

Definition

a scale that has the property of a nominal scale, but also identifies an ordering of objects in terms of the attribute

Answer 18

Ordinal variable

Question 19

Definition

a number that describe the data from a population

Answer 19

Parameter

Question 20

Definition

A number calculated with statistical techniques that tells researchers how likely it is that the results of their experiment occurred by chance and not because of the independent variable or variables; the convention in science, including social psychology, is to consider results significant if the probability level is less than 5 in 100 that the results might be due to chance factors and noth the independent variables studied

Answer 20

Probability Level (p-value)

Question 21

Definition

Variables whose values result from counting or measuring something

Answer 21

Quantitative variable

Question 22

Definition

a normal distribution with a mean of zero and standard deviation of 1

Answer 22

Standard normal distribution

Question 23

Definition

a number that describes the data from a sample

Answer 23

Statistic

Question 24

Definition

a linear transformation of test scores that expresses the distance of each score from the mean of the distribution of scores in units of the standard deviation of the distribution

Answer 24

Z score

Question 25

What are the two types of categorical data?

Answer 25

Ordinal Nominal

Question 26

What are the two types of quantitative variables?

Answer 26

Continuous Discrete

Question 27

What type of data is a grade (HD, D, C, P ...)?

Answer 27

Categorical (ordinal)

Question 28

What type of data is exam marks (89, 86.2, 69)?

Answer 28

Continuous (ratio)

Question 29

Why is it better to have continuous data?

Answer 29

It offers more information that categorical data and it can also be converted into categorical data as needed, whereas categorical data cannot be converted into continuous

Question 30

What are the two major steps in statistical tests/analyses?

Answer 30

1. Compute a test statistic, which is a value that describes the degree to which the relationship between variable or group difference vary from the null hypothesis of no difference or relationship 2. Compute a p-vaue, which estimates the likelihood in which one would see the difference described by the test statistic if the null hypothesis were true (random chance)

Question 31

What questions can you use to decide which statistical test to use?

Answer 31

* Does your data meet assumptions for parametric tests in general? * What type of variables do you have: categorical or continuous? * Repeated measurements or independent research design? * How many predictors and outcome variables? Number of levels? * So you've selected your test. The next question is whether or not your data meets the assumptions for the specific test?

Question 32

"Pei wants to examine if men are more sexually motivated than women as the literature suggests" ## Footnote **What is the IV?** **What is the DV?** **Categorical or continuous?** **What is the research design?** **How many groups/levels per IV?**

Answer 32

**What is the IV?** Sex/gender **What is the DV?** Sexual motivation **Categorical or continuous?** Continuous **What is the research design?** Between-subjects **How many groups/levels per IV?** 2 groups (male and female)

Question 33

"Does self-esteem and relationship experience predict dating anxiety?" ## Footnote **What is the IV?** **What is the DV?** **Categorical or continuous?** **What is the research design?** **How many groups/levels per IV?**

Answer 33

**What is the IV?** Self-esteem and relationship experience **What is the DV?** Dating anxiety **Categorical or continuous?** Continuous and categorical **What is the research design?** Between-subjects **How many groups/levels per IV?** Continuous and 2

Question 34

What types of questions indicate that you want to know the difference between groups?

Answer 34

Is there a difference in Y among X? Are there X difference in Y? Are there differences in group means?

Question 35

What types of questions indicate that you want to know the relationship between groups?

Answer 35

Is there a relationship between X and Y? Does X predict Y? Is there a correlation/assocation/link between X and Y?

Question 36

How do you determine causality?

Answer 36

Only by manipulating the IV in an experiment

Question 37

What types of tests can be used when you have categorical predictors/IVs?

Answer 37

T-test ANOVA Correlation (only when dichotomous) Linear regression (only when dichotomous)

Question 38

What types of tests can be used when you have continuous predictors/IVs?

Answer 38

Correlation Linear regression T-test (with conversion of continous score into groups) ANOVA (with conversion of continous score into groups)

Question 39

What are the two main types of biased samples?

Answer 39

Convenience Voluntary response

Question 40

What are the three basic prinicples of a good experiment?

Answer 40

Randomisation Repetition Control

Question 41

What proportion of the results lie within 2 SD of a normal distribution?

Answer 41

95%

Question 42

What proportion of the results lie within 1 SD of a normal distribution?

Answer 42

68%

Question 43

What proportion of the results lie within 3 SD of a normal distribution?

Answer 43

99.7%

Question 44

What is the name of the number that describes the data from a _population_?

Answer 44

Parameter

Question 45

What are the basic characteristics of a normal distribution?

Answer 45

1. The normal distribution is unimodal (1 peak) 2. The normal distribution is symmetric about its mean 3. The parameters µ and σ completely characterise the normal distribution 4. X ~ N(µ, σ), where X = variable, N = normal distribution, µ = mean and σ = SD

Question 46

What is the mean and SD of a standard normal distribution?

Answer 46

µ = 0 and σ = 1

Question 47

What is the formula that allows us to transform any normal distribution into a standard normal distribution?

Answer 47

z = (x - μ)/σ