Psy 230 Midterm 2

Front 1

What is a weighted mean? When should it be used?

Back 1

The weighted mean is the total number of scores for both groups divided by the total number of scores. It is used with uneven sample sizes.

Front 2

What measure of central tendency would you use for a normal distribution?

Back 2

Mean

Front 3

What measure of central tendency would you use for a skewed distribution?

Back 3

Median

Front 4

What measure of central tendency would you use for a distribution with extreme scores?

Back 4

Median

Front 5

What measure of central tendency would you use for a distribution with unknown or missing scores?

Back 5

Median

Front 6

What measure of central tendency would you use for a distribution with ordinal data?

Back 6

Median

Front 7

What measure of central tendency would you use for a when data is measured on a nominal scale?

Back 7

Mode

Front 8

What is a sum of squares?

Back 8

The sum of squarse is the sum of variance around the mean. Its denoted by a capital SS and its formula is sum of (x-m)^2

Front 9

Why is sum of squares an important concept in statistics?

Back 9

???

Front 10

What factors affect the variability of a distribution?

Back 10

error of measurement

high variance - more error
low variance - less error

Front 11

What is variability?

Back 11

measures the degree to which scores are spread across a distribution

Front 12

What measure of variance do you use with descriptive statistics?

Back 12

standard deviance

Front 13

What are the measures of variance?

Back 13

1. range
2. semi interquartile range
3. variance
4. standard deviation

Front 14

What is variance?

Back 14

Variance is the sum of squares divided by the total sample size.

Front 15

What measure of variance do you use with inferential statistics?

Back 15

Variance

Front 16

What is variance?

Back 16

Sum of Squares/ N

Front 17

What is the formula for population variance versus sample variance?

Back 17

Population variance SS/N
Sample Variance SS/N-1

Front 18

What measure of variance would you use for an extreme score or a score with an open ended distribution?

Back 18

Semi Interquartile Range

Front 19

What measure of variance is used as a last resort?

Back 19

Range

Front 20

What is the difference between discrete and continuous variables and which is most likely to be used for the independent variables and which for the dependent variable? Why?

Back 20

Discrete Data: A type of data is discrete if there are only a finite number of values possibl

Continuous Data:

Front 21

What is sampling error? How is it measured (generally speaking)?

Back 21

?

Front 22

In a normal distribution, the percentage of scores below (or above) the mean is what?

Back 22

the z score?

Front 23

Each Z score is equal to what measure of variance?

Back 23

Standard Deviation?

Front 24

1. The table that provides information about what percentage of the distribution is above or below a specific Z score is called what?

Back 24

Unit Normal Table

Front 25

What is a double barreled question and why is it problematic?

Back 25

When you are asking two things at once.
ex: "Should senior citizens be given more money for recreation centers and food assistance programs?"

Front 26

What is a loaded question and why is it problematic?

Back 26

A loaded question is written to lead people to respond in a certain way. it is problematic because it can influence people's answers.

Front 27

What is negative wording and why is it problematic?

Back 27

Avoid phrasing questions with negatives.
"Do you feel that the city should not approve the proposed women's shelter?"

vs.

"Do you believe that the city should approve the proposed women's shelter?"

Front 28

What are the different types of rating scales?

Back 28

Rating Scales
Open Ended Questions
Sematic Differntial Scales
Multiple Choice Scales

Front 29

Rating Scale

Back 29

*best for most situations, option of choice
Advantadges:
Structured
Specific
Easy to answer quickly

Problems:
No room for unanticipated answers
Reliable if well designed

Front 30

Open Ended Question

Back 30

Advantadges:
-most useful in early research to identify important concepts

Disadvantadges:
-Require more time and
effort to answer than
other formats
-Difficult to summarize & analyze
-Time intensive

Front 31

Semantic Differential Scales

Back 31

Advantadges:
-Used to measure values,
attitudes, or complex
relationships
-Provides data on
relative similarity of
various concepts or
attributes
-Easy to prepare & administer

Disadvantadges:
-interpretation is difficult
-Do not provide equal interval data
-Provide ordinal data at best
May have low reliability & Validity

Front 32

A likert scale

Back 32

Rating scale from 1 - 7 where respondents can circle a choice from strongly agree to strongly disagree

Front 33

Multiple Choice

Back 33

Advantadges:
-Reliable/valid if well constructed
-Easy to administer and analyze
-Provide ratio data that allow strong statistical analyses

Disadvantadge:
-Not effective for complex issues
-May force respondent to make choice when do not have an opinion

Front 34

Why is the cover letter the most important part of a survey?

Back 34

Key ingredient in getting respondent cooperation

Front 35

How many response alternative should be given on a likert scale?

Back 35

5 - 7

Front 36

What are the uses of surveys?

Back 36

-Study unobservable phenomena
-Identify knowledge (tests)
-Attitudes & beliefs
-Personality
-Satisfaction

Front 37

Why is labeling response categories a good idea?

Back 37

Labeling response categories. So that if you circle a 1 you know what you are indicating. If we dont put labels everyone is making their own scale. (It increases the validity and reliability of the scale)

Front 38

What are demand characteristics?

Back 38

Any feature of an experiment that might inform participants about the purpose of the study.

Front 39

How can you control for demand characteristics?

Back 39

Deception - make the particpants think that the experiment is studying one thing when actually it is studying something else.

Another way is to add filler items on the questionnaires (unrelated questions)

Front 40

What are floor and ceiling effects and when are they likely to occur?

Back 40

Floor Effects:When the task is too hard, everyone does really bad.

Cieling Effects: When the task is too easy, everyone gets a really high score

Front 41

What is a confound?

Back 41

A confound is a variable that varie along with the independent variable.

Front 42

Subject Mortality

Back 42

when a large number of participants are lost

(they die, or drop out)

Front 43

Regression to the Mean

Back 43

If the score on a pretest is extremely high or low, the second score will be closer to the mean value

Front 44

History

Back 44

Problem if all data for one level of the IV are collected before data for other levels.

Always collect all of your data at the same time.

Front 45

Maturation

Back 45

Is the change in your dependent variable due to the treatment or because their brain has matured. This is a problem with longitudinal studies in which data is collected over a long period of time.

Front 46

Testing

Back 46

Pre- Test : sometimes it can be a learning mechanism

Front 47

Instrumentation

Back 47

How reliable is your instrument? Make sure it gives the same reading under the same conditions at different times.

Front 48

Selection

Back 48

How you select your participants, whether they are appropriate, and how you assign them to groups.

Front 49

What is the purpose of a frequency distribution?

Back 49

- Gives us an idea of the shape of the distribution
- can get the mode

Front 50

What does column A indicate on a Unit Normal Table?

Back 50

Z score

Front 51

What does column B indicate on a Unit Normal Table?

Back 51

Proportion in Body

Front 52

What does column C indicate on a Unit Normal Table?

Back 52

Proportion in Tail

Front 53

What does column D indicate on a Unit Normal Table?

Back 53

Proportion between mean & Z

Front 54

Discrete Data

Back 54

Data that can only take certain values.

For example: the number of students in a class (you can't have half a student).

Number of students late for class
Number of crimes reported to SC police
Number of times the word number is used
Generally discrete data are counts

Front 55

Continuous Data

Back 55

Data that can take any value (within a range)

Examples: heights. People's heights could be any value (within the range of human heights), not just certain fixed heights.

Front 56

What is sampling error?

Back 56

True score + error

is the error caused by observing a sample instead of the whole population.

Front 57

Interaction

Back 57

the

Front 58

What is a main effect?

Back 58

the direct effect of an independent variable on a dependent variable

Front 59

What is an interaction?

Back 59

the unique combination of the levels of two independent variables, interaction effect is better to observe/analyze

Front 60

Why do we need to calculate central tendency and Variance?

Back 60

Central tendency tells us

Front 61

Nominal Data - What measure of variance?

Back 61

cant calculate it for nominal data

Front 62

What type of statistisc is standard deviation used with?

Back 62

Descriptive Statistics

Front 63

What type of statistics is variance used with?

Back 63

Inferential Statistics

Front 64

What are descriptive statistics?

Back 64

Use one group, for example: you want to know the gpa of everyone in this room. You are simply measuring a sub set. They describe what is there. They dont try to predict.

Front 65

What are inferential statistics?

Back 65

Using a sample to make inferences about a larger population. Standard error is corrected for in inferential statistics

Front 66

Standard Error

Back 66

the expected difference between the sample and the population mean

Front 67

What is the critical region?

Back 67

The area on the distribution above alpha.

Front 68

Two Types of Hypothesis Tests

Back 68

One tailed Test

Front 69

When we know what direction we want the mean to shift in it is called a

Back 69

One tailed test or a Directional Test

Front 70

Critical Region

Back 70

alpha = .05 is the critical region

Front 71

1. If a researcher hypothesizes that a treatment will increase the mean, will the critical region be on the left or the right side of the distribution?

Back 71

it will be on the right side

Front 72

Do one tailed or two tailed tests have the most power?

Back 72

One tailed tests have the most power.

Front 73

Steps for Hypothesis Testing

Back 73

1. State the Hypothesis
2. Select the Criterion (P value, 1 vs. 2 tailed test)
3. Collect Data and Compute Statistics
4. Decided whether to reject HO

Front 74

What is a null hypothesis?

Back 74

The hypothesis of no difference Ho
The null hypothesis = zero difference.

Front 75

What is an alternative hypothesis?

Back 75

Scientific hypothesis H1 or Ha
We always want to support the alternative hypothesis.

Front 76

What tells us the probability of getting a specific sample mean by chance?

Back 76

z score