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Transcript of experimental psychology
EXPERIMENTAL EXPERIMENTAL PSYCHOLOGYPSYCHOLOGY
Module 1Lesson 5
HYPOTHESIS
HypothesisHypothesis
Thesis, or main idea of an experimentIt is a statement about a predicted
relationship between at least two variables
Nonexperimental hypothesisNonexperimental hypothesis
Statement of your predictions of how events, traits or behaviors might be related- not a statement about cause and effect.
Experimental HypothesisExperimental Hypothesis
Tentative explanation of an event or behavior. It is a statement that predicts the effects of specified antecedent conditions on a measured behavior.
Characteristics of an Experimental Characteristics of an Experimental HypothesisHypothesis
Synthetic statements- those that can either be true or false◦Analytic statement- one that is always true◦Contradictory statements- statements with
elements that oppose each other
Characteristics of an Experimental Characteristics of an Experimental HypothesisHypothesis
Testable statements- the means for manipulating antecedent conditions and measuring the resulting behavior must exist
Falsifiable statements- disapprovable by research findings
Characteristics of an Experimental Characteristics of an Experimental HypothesisHypothesis
Fruitful- leads to new studiesParsimonious statements- simple
explanation
Process of Formulating Process of Formulating HypothesisHypothesis
Inductive Model
Deductive Model
Combination of Inductive and Deductive Model
Finding for a HypothesisFinding for a Hypothesis
Building on prior researchSerendipity and the windfall hypothesisIntuition“when all else fails…”
To establish whether the obtained sample difference is statistically significant- the result of a real population difference and not just sampling error- it is customary to set up a level of significance, denoted by the Greek letter (alpha).
Alpha value is the level of probability at which the null hypothesis can be rejected with confidence and the research hypothesis can be accepted with confidence. P < .05
To be statistically significant, the obtained value must exceed or be less than the critical value depending on the test used.
Levels of SignificanceLevels of Significance
DECISION Retain Null Reject Null
RE Null isA TrueLIT Null isY False
Type I and II ErrorsType I and II Errors
CORRECT DECISION
Type I Error p(Type I Error) =
Type II Error p(Type II Error)=
CORRECT DECISION
P is the exact probability that the null hypothesis is true in light of the sample data.
The alpha value is the threshold below which is considered so small that we decide to reject the null hypothesis.
Decision to reject the null hypothesis is made if the P value is less than the alpha value and otherwise retain it. NOTE: FOR A Z TEST
HOWEVER, for a t test, the computed t must be greater than or equal to the value of the alpha level set.
What is the difference between p and What is the difference between p and ??
STEPS in STEPS in HYPOTHESIS TESTINGHYPOTHESIS TESTING
SAMPLE ACTIVITY:The One-Way Analysis of Variance
(ANOVA)
Chapter 13 - 15
PROBLEM1– Sincerity Scale by Year LevelPROBLEM1– Sincerity Scale by Year LevelUsing the following data set, conduct a one-way ANOVA among students of DLSU-D, at 0.01 determine the significant difference of the independent variable. Provide the summary table. Give a post hoc (?) if significant. Apply the steps in Hypothesis Testing.
totalX 2totalX NtotalX
1st year 2nd year 3rd year 4th year
20 19 10 11
19 18 11 11
17 18 15 10
15 15 11 10
15 16 15 12
16 16 14 11
17 10 10 13
3X22X2X
21X 2
3X1X 24X4X
1191 X 21X 2
2X 23X1122 X 863 X
1X71 n 72 n 73 n2X 3X
784 X 24X
4X74 n
Chapter 13 - 16
Source Sum of df Mean FSquares Squares
BetweenWithinTotal*fcrit at α 0.05 -- ?Not Significant/ Significant**fcrit at α 0.01 -- ?Not Significant/ Significant
Compute your Compute your f-ratiof-ratio, then, provide the , then, provide the Summary Table of F-ratioSummary Table of F-ratio
Chapter 13 - 17
?)( wn
n
MSqHSD k
Post Hoc (When to use?)Post Hoc (When to use?)
?
?
?
?
?
?
43
42
32
41
31
21
XX
XX
XX
XX
XX
XX
Chapter 11 - 18
Perform the Steps in Hypothesis Testing:Step 1: Formulate your H0: and Ha:Step 2: Identify your
at 0.01 the Step 3: Compute the F-testStep 4: Decision:
Accept Ho; or Reject Ho then Accept Ha
Step 5: Conclusion: Therefore, _____
?crit f
PROBLEM1– Sincerity Scale by Year Level
ANSWERSANSWERS
Chapter 13 - 20
Source Sum of df Mean FSquares Squares
Between 168.39 3 56.13 11.79Within 114.29 24 4.76Total 282.68 27*fcrit at α 0.05 -- 3.01 Significant**fcrit at α 0.01 -- 4.72 Significant
ANSWERANSWERSummary Table of F-ratioSummary Table of F-ratio
Chapter 13 - 21
68.28228
3955855
)( 22tot2
tottot
N
XXSS
39.16828
395
7
78
7
86
7
112
7
119
)(
columntheinscoresof
)columntheinscoresofsum(
22222
2tot
2
bn
N
X
nSS
29.11439.16868.282bntotwn SSSSSS
SUMS of Squares SUMS of Squares
Chapter 13 - 22
Degrees of FreedomDegrees of Freedom
dfbn = k - 1 = 4 - 1 = 3 Numerator
dfwn = N - k = 28 - 4 = 24 Denominator
dftot = N - 1 = 28 - 1 = 27
Chapter 13 - 23
13.563
39.168
bn
bnbn
df
SSMS
76.424
29.114
wn
wnwn
df
SSMS
79.1176.4
13.56
wn
bnobt
MS
MSF
Mean of Squares and FMean of Squares and Fobtobt
Chapter 13 - 24
degrees of freedom (df= 3 and 24)
Fcrit (4.72) at 0.01.
Since Fobt = 11.79, the ANOVA is significant
SIGNIFICANCE then, use Tukey.
Chapter 13 - 25
05.47
76.491.4)( wn
n
MSqHSD k
Post HocPost Hoc
15.1
86.4
71.3
86.5
71.4
0.1
43
42
32
41
31
21
XX
XX
XX
XX
XX
XX
Chapter 11 - 26
Perform the Steps in Hypothesis Testing:Step 1: Formulate your H0: and Ha:Step 2: Identify your
dfb= 3, dfw= 24, dftot= 27 at 0.01 the
Step 3: Compute the f-ratio Step 4: Decision:
Reject Ho, then Accept HaStep 5: Conclusion:
Therefore, there is A SIGNIFICANT difference…
72.4crit f
PROBLEM1– Sincerity Scale by Year Level
79.11obt f
EXPERIMENTAL EXPERIMENTAL PSYCHOLOGYPSYCHOLOGY
QUIZ # 3QUIZ # 3
Multiple choice: Multiple choice: Write the letter of Write the letter of the correct answer. (2pts each)the correct answer. (2pts each)
1. A good experimental title for a report should _____.
a. provide summary of essential resultsb. give an idea of what the report is aboutc. state the major experimental hypothesisd. include the names of the authore. all of the above
2. Our manuscript for this subject should follow the format given by ___.
a. APA Publication Manualb. Manual of the Psychonomic societyc. Science Foundation Manuald. Style Guide for Psychological Reportse. DSM V
3. Which of the following is not a major section of the research report?
a. introduction b. method c. prologue d. results e. discussion
4. A good and standard length for an abstract in a journal would be about ___.
a. 50 to 75 words b. 100-120words c. 200-300 words d. 150-200 words
5. The purpose of the Discussion section is to ____.
a. explain non-significant findingsb. evaluate and interpret the resultsc. summarize the studyd. justify continued experimentatione. review all prior research in the area
B. Indicate what section of the manuscript B. Indicate what section of the manuscript where the following could be found. where the following could be found. (2 pts each)(2 pts each)
1. A tentative assumption of the study.2. F(1,2) = 6.26, p< .013. summary of the study4. review of related literature5. table of data and figures6. Includes subsections such as participants,
apparatus and procedure7. list of books used for the review of related
literature8. generalization and conclusions of the study.9. narrative description of data10. recommendations of the study.
C. APPLICATION (2 pts. Each)C. APPLICATION (2 pts. Each)A researcher reported that A researcher reported that t (?) 6.875, t (?) 6.875, αα = .05; n=49; = .05; n=49; with tabulated value of with tabulated value of 3.143.14.. (Decisiveness and Mental Ability)(Decisiveness and Mental Ability)
1. Was the null hypothesis rejected?2. How many percent are you confident
that the obtained value did not occur by chance alone?
3. What was the degree of freedom?4. Was there significant difference between
the groups being compared? Explain Why.
ANSWERSANSWERS
1. B2. A/D3. C4. B5. B
1. Hypothesis (Introduction)
2. Result3. Abstract or Discussion4. Introduction5. Result6. Methods7. References8. Discussion9. Method10. Discussion
1. Yes…Ho: There is no significant difference on the level of decisiveness among participants with varying mental ability.
2. 95 % of confidence3. df=48 (n-1)4. Yes, since the tobt (6.875) is > tcrit (3.14)
at α = .05. This implies that there is a significant difference between the two groups being studied.