SlideShare a Scribd company logo
Stroop Effect P1
Q: What is our independent variable? What is our dependent variable?
A: The independent variable is the two forms of the test either color matching word or color
mismatching word. The dependent variable is reaction time between the task and response.[1]
Q: What is an appropriate set of hypotheses for this task? What kind of statistical test do you
expect to perform? Justify your choices.
A: Two hypotheses are most likely to occur. Either there will be no too little effect in the test
results creating a null hypothesis. However, an alternate hypothesis may show results that color
matching word has a lower response time than color mismatching word.[1]
Indicating that the
incongruent’s reaction time data is significantly higher than the congruent’s reaction time data.
• Null Hypothesis H0 = The data between the two results will not differ significantly. In
which the t-statistic do not differ from alpha of 0.05. In which Ho : µ1 = µ2
[7]
• Alternative Hypothesis H1 = There will be a non-random significant difference between
the data of the two results. In which the t-statistic differ from alpha of 0.05. In which H1 :
µ1 = µ2
[7]
• µ1 is the mean of population 1 and µ2 is the mean of population 2.
We can use a two sample T-Test considering the sample size is less than 30 and the standard
deviation of the population is unknown.[6]
Also both populations are independent for data, but
each person has two measurements.[5]
Q: Report some descriptive statistics regarding this dataset. Include at least one measure of
central tendency and at least one measure of variability.
A:
Congruent Incongruent
Mean 14.05 22.02
Mode N/A N/A
Median 14.36 21.02
Variance 12.67 23.01
Std.Deviation 3.56 4.80
IQR 4.31 5.33
Range 13.70 8.84
Q: Provide one or two visualizations that show the distribution of the sample data. Write one or
two sentences noting what you observe about the plot or plots.
Fig 1: Statistical analysis of
Congruent and Incongruent
Stroop data.
.
We can see from all three figures that on average the reaction time when performing
congruent test is lower than that of the incongruent test for the subjects. From figure 2 with
removal of the outlier using the IQR range we can see the congruent curve is positively skewed,
while the incongruent curve is more of a normal distribution. This might be indicative that some
0
2
4
6
8
0 4 8 12 16 20 24 28 32 36 40
Frequency
Reaction Time (seconds)
Congruent Vs. Incongruent
Without Ourliers
Congruent
Incongruent
0
2
4
6
8
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30
Frequency
Reaction Time (s)
Congruent Vs. Incongruent
Without Ourliers
Congruent
Incongruent
0.00
5.00
10.00
15.00
20.00
25.00
Congruent Incongruent
ReactionTime(S)
Average Reaction Time
Congruent Vs. Incongruent
Fig 2: Congruent Vs
Incongruent histogram with
outliers.[2]
Fig 3: Congruent Vs
Incongruent histogram
without outliers.[2]
Fig 4: Average reaction time
of Congruent Vs Incongruent
individuals are not as greatly affected by the incongruent task as others. While most individuals
are able to perform the congruent task with ease.
Q: Now, perform the statistical test and report your results. What is your confidence level and
your critical statistic value? Do you reject the null hypothesis or fail to reject it? Come to a
conclusion in terms of the experiment task. Did the results match up with your expectations?
A: Confidence level is 95%, Critical statistic value 0.05[3]
Congruent Incongruent Difference
Mean 14.05 22.02 -7.96
Variance 12.67 23.01
Observations 24 24
Pearson Correlation 0.35
Hypothesized Mean Difference 0
df 23
t Stat -8.0207
P(T<=t) one-tail 2.052E-08
t Critical one-tail 1.7139
P(T<=t) two-tail 4.103E-08
t Critical two-tail 2.069
Since P-Value two-tail for the T-Test is less than critical statistic value of 0.05. In conclusion I
reject the null hypothesis and support the alternative hypothesis.[3]
. There is a significant
difference between mean times for the task. It does take significantly longer to complete the
incongruent task as compared to the congruent task. This is seen by the difference of the
means of approximately -7.96 seconds. These results do match my expectations and are in line
with the results I received when taking the Stroop test myself.
Q: What do you think is responsible for the effects observed? Can you think of an alternative or
similar task that would result in a similar effect? Some research about the problem will be
helpful for thinking about these two questions!
A: This may be due to humans being conditioned to deciphering words in everyday life that our
brains automatically focus on figuring out the word and ignore color initially unless forced to.
This reduces the reaction time of the person as they have use time confirming the color. You
could perform a numerical test where the numbers differ in both numerical and physical size and
ask participants which number is numerically larger.[4]
References:
[1]: Stroop, J.R. Studies of interference in serial verbal reactions. J. Exp. Psychol., 18:643-662,
1935
Fig 4: Two Sample T-Test[3]
[2]: Create A Histogram. (n.d.). Retrieved January 17, 2017, from
https://support.office.com/en-us/article/Create-a-histogram-b6814e9e-5860-4113-ba51-
e3a1b9ee1bbe
[3]: Chieh, C. J. (n.d.). Making Sense of the Two-Sample T-Test. Retrieved January 17,
2017, from https://www.isixsigma.com/tools-templates/hypothesis-testing/making-sense-two-sample-
t-test/
[4]: Henik, A. & Tzelgov, J. Mem Cogn (1982) 10: 389. doi:10.3758/BF03202431
[5]: Types of T-Test. Retrieved January 17, 2017. from http://support.minitab.com/en-
us/minitab/17/topic-library/basic-statistics-and-graphs/hypothesis-tests/tests-of-means/types-of-
t-tests/
[6]: Andale. T-Score Vs. Z-Score What’s the difference? Published August 23, 2013,
Retrieved January 17, 2017. From http://www.statisticshowto.com/when-to-use-a-t-score-vs-z-
score/
[7]: What is Hypothesis Testing?. Retrieved January 17, 2017. From
http://stattrek.com/hypothesis-test/hypothesis-testing.aspx

More Related Content

What's hot

Faces Lab Report
Faces Lab ReportFaces Lab Report
Faces Lab Report
William Teng
 
Seawell_Exam
Seawell_ExamSeawell_Exam
Seawell_Exam
Tiffany Seawell
 
Emil Pulido on Quantitative Research: Inferential Statistics
Emil Pulido on Quantitative Research: Inferential StatisticsEmil Pulido on Quantitative Research: Inferential Statistics
Emil Pulido on Quantitative Research: Inferential Statistics
EmilEJP
 
Definitions of Econometric
Definitions of Econometric Definitions of Econometric
Definitions of Econometric
Qamar Farooq
 
Introduction to Hypothesis Testing
Introduction to Hypothesis TestingIntroduction to Hypothesis Testing
Introduction to Hypothesis Testing
jasondroesch
 
T test
T testT test
Distinction between outliers and influential data points w out hyp test
Distinction between outliers and influential data points w out hyp testDistinction between outliers and influential data points w out hyp test
Distinction between outliers and influential data points w out hyp test
Aditya Praveen Kumar
 
Les5e ppt 11
Les5e ppt 11Les5e ppt 11
Les5e ppt 11
Subas Nandy
 
What is a Wilcoxon Sign-Ranked Test (pair t non para)?
What is a Wilcoxon Sign-Ranked Test (pair t non para)?What is a Wilcoxon Sign-Ranked Test (pair t non para)?
What is a Wilcoxon Sign-Ranked Test (pair t non para)?
Ken Plummer
 
Stats chapter 13
Stats chapter 13Stats chapter 13
Stats chapter 13
Richard Ferreria
 
Goodness Of Fit Test
Goodness Of Fit TestGoodness Of Fit Test
Goodness Of Fit Test
Kishan Kasundra
 
Sign test
Sign testSign test
Sign test
sukhpal0015
 
Inferential Statistics
Inferential StatisticsInferential Statistics
Inferential Statistics
University of Jaffna
 
HYPOTHESIS TESTING
HYPOTHESIS TESTINGHYPOTHESIS TESTING
HYPOTHESIS TESTING
Amna Sheikh
 
Statistical parameters
Statistical parametersStatistical parameters
Statistical parameters
Burdwan University
 
D. Mayo: Philosophy of Statistics & the Replication Crisis in Science
D. Mayo: Philosophy of Statistics & the Replication Crisis in ScienceD. Mayo: Philosophy of Statistics & the Replication Crisis in Science
D. Mayo: Philosophy of Statistics & the Replication Crisis in Science
jemille6
 
Chi square test
Chi square testChi square test
Chi square test
callr
 
Lecture note 2
Lecture note 2Lecture note 2
Lecture note 2
sreenu t
 

What's hot (18)

Faces Lab Report
Faces Lab ReportFaces Lab Report
Faces Lab Report
 
Seawell_Exam
Seawell_ExamSeawell_Exam
Seawell_Exam
 
Emil Pulido on Quantitative Research: Inferential Statistics
Emil Pulido on Quantitative Research: Inferential StatisticsEmil Pulido on Quantitative Research: Inferential Statistics
Emil Pulido on Quantitative Research: Inferential Statistics
 
Definitions of Econometric
Definitions of Econometric Definitions of Econometric
Definitions of Econometric
 
Introduction to Hypothesis Testing
Introduction to Hypothesis TestingIntroduction to Hypothesis Testing
Introduction to Hypothesis Testing
 
T test
T testT test
T test
 
Distinction between outliers and influential data points w out hyp test
Distinction between outliers and influential data points w out hyp testDistinction between outliers and influential data points w out hyp test
Distinction between outliers and influential data points w out hyp test
 
Les5e ppt 11
Les5e ppt 11Les5e ppt 11
Les5e ppt 11
 
What is a Wilcoxon Sign-Ranked Test (pair t non para)?
What is a Wilcoxon Sign-Ranked Test (pair t non para)?What is a Wilcoxon Sign-Ranked Test (pair t non para)?
What is a Wilcoxon Sign-Ranked Test (pair t non para)?
 
Stats chapter 13
Stats chapter 13Stats chapter 13
Stats chapter 13
 
Goodness Of Fit Test
Goodness Of Fit TestGoodness Of Fit Test
Goodness Of Fit Test
 
Sign test
Sign testSign test
Sign test
 
Inferential Statistics
Inferential StatisticsInferential Statistics
Inferential Statistics
 
HYPOTHESIS TESTING
HYPOTHESIS TESTINGHYPOTHESIS TESTING
HYPOTHESIS TESTING
 
Statistical parameters
Statistical parametersStatistical parameters
Statistical parameters
 
D. Mayo: Philosophy of Statistics & the Replication Crisis in Science
D. Mayo: Philosophy of Statistics & the Replication Crisis in ScienceD. Mayo: Philosophy of Statistics & the Replication Crisis in Science
D. Mayo: Philosophy of Statistics & the Replication Crisis in Science
 
Chi square test
Chi square testChi square test
Chi square test
 
Lecture note 2
Lecture note 2Lecture note 2
Lecture note 2
 

Viewers also liked

Marketing
MarketingMarketing
Marketing
mkvengatesh
 
Marketing
MarketingMarketing
Marketing
mkvengatesh
 
Portfolio mark
Portfolio markPortfolio mark
Portfolio mark
mark rademakers
 
BLINKit _MEDIA KIT_
BLINKit _MEDIA KIT_BLINKit _MEDIA KIT_
BLINKit _MEDIA KIT_
Lila Romero
 
CJUS 4901.001 Research Paper
CJUS 4901.001 Research PaperCJUS 4901.001 Research Paper
CJUS 4901.001 Research Paper
Jonathan L. Bell
 
2017 calender-nyuko
2017 calender-nyuko2017 calender-nyuko
2017 calender-nyuko
たびせん つなぐ
 
Marketing
MarketingMarketing
Marketing
mkvengatesh
 
Multimedia-2016_Brochure
Multimedia-2016_BrochureMultimedia-2016_Brochure
Multimedia-2016_Brochure
Gracie jones
 
Mental retardation
Mental retardationMental retardation
Mental retardation
18Diosa
 
splashmedia-BarLouie-PokemonGO
splashmedia-BarLouie-PokemonGOsplashmedia-BarLouie-PokemonGO
splashmedia-BarLouie-PokemonGO
Brandon Wainerdi
 
marketing plsn
marketing plsnmarketing plsn
marketing plsn
SHASHANK SHEKHAR
 
Signia Siemens Hearing Aid Product Portfolio
Signia Siemens Hearing Aid Product PortfolioSignia Siemens Hearing Aid Product Portfolio
Signia Siemens Hearing Aid Product Portfolio
Gurgaon Hearing Aids Center
 
3.1. clases de palabras
3.1. clases de palabras3.1. clases de palabras
3.1. clases de palabras
Inmaculada Camacho López
 
Varias.modelo2.castillala manchalen
Varias.modelo2.castillala manchalenVarias.modelo2.castillala manchalen
Varias.modelo2.castillala manchalen
Memodi Regalos
 
Το σχολείο που θέλουν τα παιδιά
Το σχολείο που θέλουν τα παιδιάΤο σχολείο που θέλουν τα παιδιά
Το σχολείο που θέλουν τα παιδιά
FRANTIOPI
 
¿Qué es drupal?
¿Qué es drupal? ¿Qué es drupal?
¿Qué es drupal?
Atenea tech
 
Envolver pacientes e cuidadores- Tópico 8_Guia curricular da OMS
Envolver pacientes e cuidadores- Tópico 8_Guia curricular da OMSEnvolver pacientes e cuidadores- Tópico 8_Guia curricular da OMS
Envolver pacientes e cuidadores- Tópico 8_Guia curricular da OMS
Proqualis
 

Viewers also liked (17)

Marketing
MarketingMarketing
Marketing
 
Marketing
MarketingMarketing
Marketing
 
Portfolio mark
Portfolio markPortfolio mark
Portfolio mark
 
BLINKit _MEDIA KIT_
BLINKit _MEDIA KIT_BLINKit _MEDIA KIT_
BLINKit _MEDIA KIT_
 
CJUS 4901.001 Research Paper
CJUS 4901.001 Research PaperCJUS 4901.001 Research Paper
CJUS 4901.001 Research Paper
 
2017 calender-nyuko
2017 calender-nyuko2017 calender-nyuko
2017 calender-nyuko
 
Marketing
MarketingMarketing
Marketing
 
Multimedia-2016_Brochure
Multimedia-2016_BrochureMultimedia-2016_Brochure
Multimedia-2016_Brochure
 
Mental retardation
Mental retardationMental retardation
Mental retardation
 
splashmedia-BarLouie-PokemonGO
splashmedia-BarLouie-PokemonGOsplashmedia-BarLouie-PokemonGO
splashmedia-BarLouie-PokemonGO
 
marketing plsn
marketing plsnmarketing plsn
marketing plsn
 
Signia Siemens Hearing Aid Product Portfolio
Signia Siemens Hearing Aid Product PortfolioSignia Siemens Hearing Aid Product Portfolio
Signia Siemens Hearing Aid Product Portfolio
 
3.1. clases de palabras
3.1. clases de palabras3.1. clases de palabras
3.1. clases de palabras
 
Varias.modelo2.castillala manchalen
Varias.modelo2.castillala manchalenVarias.modelo2.castillala manchalen
Varias.modelo2.castillala manchalen
 
Το σχολείο που θέλουν τα παιδιά
Το σχολείο που θέλουν τα παιδιάΤο σχολείο που θέλουν τα παιδιά
Το σχολείο που θέλουν τα παιδιά
 
¿Qué es drupal?
¿Qué es drupal? ¿Qué es drupal?
¿Qué es drupal?
 
Envolver pacientes e cuidadores- Tópico 8_Guia curricular da OMS
Envolver pacientes e cuidadores- Tópico 8_Guia curricular da OMSEnvolver pacientes e cuidadores- Tópico 8_Guia curricular da OMS
Envolver pacientes e cuidadores- Tópico 8_Guia curricular da OMS
 

Similar to P1 Stroop

Analyzing experimental research data
Analyzing experimental research dataAnalyzing experimental research data
Analyzing experimental research data
Atula Ahuja
 
11 T(EA) FOR TWO TESTS BETWEEN THE MEANS OF DIFFERENT GROUPS11 .docx
11 T(EA) FOR TWO TESTS BETWEEN THE MEANS OF DIFFERENT GROUPS11 .docx11 T(EA) FOR TWO TESTS BETWEEN THE MEANS OF DIFFERENT GROUPS11 .docx
11 T(EA) FOR TWO TESTS BETWEEN THE MEANS OF DIFFERENT GROUPS11 .docx
novabroom
 
11 T(EA) FOR TWO TESTS BETWEEN THE MEANS OF DIFFERENT GROUPS11 .docx
11 T(EA) FOR TWO TESTS BETWEEN THE MEANS OF DIFFERENT GROUPS11 .docx11 T(EA) FOR TWO TESTS BETWEEN THE MEANS OF DIFFERENT GROUPS11 .docx
11 T(EA) FOR TWO TESTS BETWEEN THE MEANS OF DIFFERENT GROUPS11 .docx
hyacinthshackley2629
 
HYPOTHESES.pptx
HYPOTHESES.pptxHYPOTHESES.pptx
HYPOTHESES.pptx
TalhaKhan420569
 
Topic 10 DATA ANALYSIS TECHNIQUES.pptx
Topic 10 DATA ANALYSIS TECHNIQUES.pptxTopic 10 DATA ANALYSIS TECHNIQUES.pptx
Topic 10 DATA ANALYSIS TECHNIQUES.pptx
EdwinDagunot4
 
T test
T test T test
Marketing Research Hypothesis Testing.pptx
Marketing Research Hypothesis Testing.pptxMarketing Research Hypothesis Testing.pptx
Marketing Research Hypothesis Testing.pptx
xababid981
 
Directions The purpose of Project 8 is to prepare you for the final.docx
Directions The purpose of Project 8 is to prepare you for the final.docxDirections The purpose of Project 8 is to prepare you for the final.docx
Directions The purpose of Project 8 is to prepare you for the final.docx
eve2xjazwa
 
Data analysis
Data analysisData analysis
Data analysis
metalkid132
 
© 2014 Laureate Education, Inc. Page 1 of 5 Week 4 A.docx
© 2014 Laureate Education, Inc.   Page 1 of 5  Week 4 A.docx© 2014 Laureate Education, Inc.   Page 1 of 5  Week 4 A.docx
© 2014 Laureate Education, Inc. Page 1 of 5 Week 4 A.docx
gerardkortney
 
Applied statistics lecture_3
Applied statistics lecture_3Applied statistics lecture_3
Applied statistics lecture_3
Daria Bogdanova
 
non para.doc
non para.docnon para.doc
non para.doc
Annamalai University
 
Assessment 3 – Hypothesis, Effect Size, Power, and t Tests.docx
Assessment 3 – Hypothesis, Effect Size, Power, and t Tests.docxAssessment 3 – Hypothesis, Effect Size, Power, and t Tests.docx
Assessment 3 – Hypothesis, Effect Size, Power, and t Tests.docx
cargillfilberto
 
T-Test
T-TestT-Test
PAGE O&M Statistics – Inferential Statistics Hypothesis Test.docx
PAGE  O&M Statistics – Inferential Statistics Hypothesis Test.docxPAGE  O&M Statistics – Inferential Statistics Hypothesis Test.docx
PAGE O&M Statistics – Inferential Statistics Hypothesis Test.docx
gerardkortney
 
This is my statistics exam I need help I have been lost this whole s.docx
This is my statistics exam I need help I have been lost this whole s.docxThis is my statistics exam I need help I have been lost this whole s.docx
This is my statistics exam I need help I have been lost this whole s.docx
divinapavey
 
Analyzing experimental research data
Analyzing experimental research dataAnalyzing experimental research data
Analyzing experimental research data
Atula Ahuja
 
The t Test for Two Related Samples
The t Test for Two Related SamplesThe t Test for Two Related Samples
The t Test for Two Related Samples
Mary Anne (Riyan) Portuguez
 
Spss2 comparing means_two_groups
Spss2 comparing means_two_groupsSpss2 comparing means_two_groups
Spss2 comparing means_two_groups
riddhu12
 
Ttest
TtestTtest

Similar to P1 Stroop (20)

Analyzing experimental research data
Analyzing experimental research dataAnalyzing experimental research data
Analyzing experimental research data
 
11 T(EA) FOR TWO TESTS BETWEEN THE MEANS OF DIFFERENT GROUPS11 .docx
11 T(EA) FOR TWO TESTS BETWEEN THE MEANS OF DIFFERENT GROUPS11 .docx11 T(EA) FOR TWO TESTS BETWEEN THE MEANS OF DIFFERENT GROUPS11 .docx
11 T(EA) FOR TWO TESTS BETWEEN THE MEANS OF DIFFERENT GROUPS11 .docx
 
11 T(EA) FOR TWO TESTS BETWEEN THE MEANS OF DIFFERENT GROUPS11 .docx
11 T(EA) FOR TWO TESTS BETWEEN THE MEANS OF DIFFERENT GROUPS11 .docx11 T(EA) FOR TWO TESTS BETWEEN THE MEANS OF DIFFERENT GROUPS11 .docx
11 T(EA) FOR TWO TESTS BETWEEN THE MEANS OF DIFFERENT GROUPS11 .docx
 
HYPOTHESES.pptx
HYPOTHESES.pptxHYPOTHESES.pptx
HYPOTHESES.pptx
 
Topic 10 DATA ANALYSIS TECHNIQUES.pptx
Topic 10 DATA ANALYSIS TECHNIQUES.pptxTopic 10 DATA ANALYSIS TECHNIQUES.pptx
Topic 10 DATA ANALYSIS TECHNIQUES.pptx
 
T test
T test T test
T test
 
Marketing Research Hypothesis Testing.pptx
Marketing Research Hypothesis Testing.pptxMarketing Research Hypothesis Testing.pptx
Marketing Research Hypothesis Testing.pptx
 
Directions The purpose of Project 8 is to prepare you for the final.docx
Directions The purpose of Project 8 is to prepare you for the final.docxDirections The purpose of Project 8 is to prepare you for the final.docx
Directions The purpose of Project 8 is to prepare you for the final.docx
 
Data analysis
Data analysisData analysis
Data analysis
 
© 2014 Laureate Education, Inc. Page 1 of 5 Week 4 A.docx
© 2014 Laureate Education, Inc.   Page 1 of 5  Week 4 A.docx© 2014 Laureate Education, Inc.   Page 1 of 5  Week 4 A.docx
© 2014 Laureate Education, Inc. Page 1 of 5 Week 4 A.docx
 
Applied statistics lecture_3
Applied statistics lecture_3Applied statistics lecture_3
Applied statistics lecture_3
 
non para.doc
non para.docnon para.doc
non para.doc
 
Assessment 3 – Hypothesis, Effect Size, Power, and t Tests.docx
Assessment 3 – Hypothesis, Effect Size, Power, and t Tests.docxAssessment 3 – Hypothesis, Effect Size, Power, and t Tests.docx
Assessment 3 – Hypothesis, Effect Size, Power, and t Tests.docx
 
T-Test
T-TestT-Test
T-Test
 
PAGE O&M Statistics – Inferential Statistics Hypothesis Test.docx
PAGE  O&M Statistics – Inferential Statistics Hypothesis Test.docxPAGE  O&M Statistics – Inferential Statistics Hypothesis Test.docx
PAGE O&M Statistics – Inferential Statistics Hypothesis Test.docx
 
This is my statistics exam I need help I have been lost this whole s.docx
This is my statistics exam I need help I have been lost this whole s.docxThis is my statistics exam I need help I have been lost this whole s.docx
This is my statistics exam I need help I have been lost this whole s.docx
 
Analyzing experimental research data
Analyzing experimental research dataAnalyzing experimental research data
Analyzing experimental research data
 
The t Test for Two Related Samples
The t Test for Two Related SamplesThe t Test for Two Related Samples
The t Test for Two Related Samples
 
Spss2 comparing means_two_groups
Spss2 comparing means_two_groupsSpss2 comparing means_two_groups
Spss2 comparing means_two_groups
 
Ttest
TtestTtest
Ttest
 

P1 Stroop

  • 1. Stroop Effect P1 Q: What is our independent variable? What is our dependent variable? A: The independent variable is the two forms of the test either color matching word or color mismatching word. The dependent variable is reaction time between the task and response.[1] Q: What is an appropriate set of hypotheses for this task? What kind of statistical test do you expect to perform? Justify your choices. A: Two hypotheses are most likely to occur. Either there will be no too little effect in the test results creating a null hypothesis. However, an alternate hypothesis may show results that color matching word has a lower response time than color mismatching word.[1] Indicating that the incongruent’s reaction time data is significantly higher than the congruent’s reaction time data. • Null Hypothesis H0 = The data between the two results will not differ significantly. In which the t-statistic do not differ from alpha of 0.05. In which Ho : µ1 = µ2 [7] • Alternative Hypothesis H1 = There will be a non-random significant difference between the data of the two results. In which the t-statistic differ from alpha of 0.05. In which H1 : µ1 = µ2 [7] • µ1 is the mean of population 1 and µ2 is the mean of population 2. We can use a two sample T-Test considering the sample size is less than 30 and the standard deviation of the population is unknown.[6] Also both populations are independent for data, but each person has two measurements.[5] Q: Report some descriptive statistics regarding this dataset. Include at least one measure of central tendency and at least one measure of variability. A: Congruent Incongruent Mean 14.05 22.02 Mode N/A N/A Median 14.36 21.02 Variance 12.67 23.01 Std.Deviation 3.56 4.80 IQR 4.31 5.33 Range 13.70 8.84 Q: Provide one or two visualizations that show the distribution of the sample data. Write one or two sentences noting what you observe about the plot or plots. Fig 1: Statistical analysis of Congruent and Incongruent Stroop data.
  • 2. . We can see from all three figures that on average the reaction time when performing congruent test is lower than that of the incongruent test for the subjects. From figure 2 with removal of the outlier using the IQR range we can see the congruent curve is positively skewed, while the incongruent curve is more of a normal distribution. This might be indicative that some 0 2 4 6 8 0 4 8 12 16 20 24 28 32 36 40 Frequency Reaction Time (seconds) Congruent Vs. Incongruent Without Ourliers Congruent Incongruent 0 2 4 6 8 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 Frequency Reaction Time (s) Congruent Vs. Incongruent Without Ourliers Congruent Incongruent 0.00 5.00 10.00 15.00 20.00 25.00 Congruent Incongruent ReactionTime(S) Average Reaction Time Congruent Vs. Incongruent Fig 2: Congruent Vs Incongruent histogram with outliers.[2] Fig 3: Congruent Vs Incongruent histogram without outliers.[2] Fig 4: Average reaction time of Congruent Vs Incongruent
  • 3. individuals are not as greatly affected by the incongruent task as others. While most individuals are able to perform the congruent task with ease. Q: Now, perform the statistical test and report your results. What is your confidence level and your critical statistic value? Do you reject the null hypothesis or fail to reject it? Come to a conclusion in terms of the experiment task. Did the results match up with your expectations? A: Confidence level is 95%, Critical statistic value 0.05[3] Congruent Incongruent Difference Mean 14.05 22.02 -7.96 Variance 12.67 23.01 Observations 24 24 Pearson Correlation 0.35 Hypothesized Mean Difference 0 df 23 t Stat -8.0207 P(T<=t) one-tail 2.052E-08 t Critical one-tail 1.7139 P(T<=t) two-tail 4.103E-08 t Critical two-tail 2.069 Since P-Value two-tail for the T-Test is less than critical statistic value of 0.05. In conclusion I reject the null hypothesis and support the alternative hypothesis.[3] . There is a significant difference between mean times for the task. It does take significantly longer to complete the incongruent task as compared to the congruent task. This is seen by the difference of the means of approximately -7.96 seconds. These results do match my expectations and are in line with the results I received when taking the Stroop test myself. Q: What do you think is responsible for the effects observed? Can you think of an alternative or similar task that would result in a similar effect? Some research about the problem will be helpful for thinking about these two questions! A: This may be due to humans being conditioned to deciphering words in everyday life that our brains automatically focus on figuring out the word and ignore color initially unless forced to. This reduces the reaction time of the person as they have use time confirming the color. You could perform a numerical test where the numbers differ in both numerical and physical size and ask participants which number is numerically larger.[4] References: [1]: Stroop, J.R. Studies of interference in serial verbal reactions. J. Exp. Psychol., 18:643-662, 1935 Fig 4: Two Sample T-Test[3]
  • 4. [2]: Create A Histogram. (n.d.). Retrieved January 17, 2017, from https://support.office.com/en-us/article/Create-a-histogram-b6814e9e-5860-4113-ba51- e3a1b9ee1bbe [3]: Chieh, C. J. (n.d.). Making Sense of the Two-Sample T-Test. Retrieved January 17, 2017, from https://www.isixsigma.com/tools-templates/hypothesis-testing/making-sense-two-sample- t-test/ [4]: Henik, A. & Tzelgov, J. Mem Cogn (1982) 10: 389. doi:10.3758/BF03202431 [5]: Types of T-Test. Retrieved January 17, 2017. from http://support.minitab.com/en- us/minitab/17/topic-library/basic-statistics-and-graphs/hypothesis-tests/tests-of-means/types-of- t-tests/ [6]: Andale. T-Score Vs. Z-Score What’s the difference? Published August 23, 2013, Retrieved January 17, 2017. From http://www.statisticshowto.com/when-to-use-a-t-score-vs-z- score/ [7]: What is Hypothesis Testing?. Retrieved January 17, 2017. From http://stattrek.com/hypothesis-test/hypothesis-testing.aspx