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Class experiment: introduce t-tests and more,

with haiku poems.

Paul RobackSt. Olaf College

CAUSE Activity WebinarJune 22, 2010

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Describe short (10-15 min) in-class experiment that produces: Data for two-group comparisons Opportunities for discussion about practical

experimental design decisions in published research

Opportunities for discussion about significance, causation, and generalizability

Creative poetry about statistics Target audience:

First day of second applied course Introductory stats students

Overview

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Case Study 1.1.1 in The Statistical Sleuth

Amabile, Teresa M. 1985. "Motivation and Creativity: Effects of Motivational Orientation on Creative Writers", Journal of Personality and Social Psychology 48(2): 393-399

Motivation

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Syllabus Course objectives Grading policies Honor code statement Blah, blah, blah …

Before eyelids get too heavy… Each student randomly receives one

of two questionnaires

The first day ofStatistical Modeling…

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INSTRUCTIONS: Please rank the following list of reasons for writing, in order of personal importance to you (1=highest, 7=lowest).

___ You get a lot of pleasure out of reading something good that you have written.

___ You enjoy the opportunity for self-expression.___ You achieve new insights through your writing.___ You derive satisfaction from expressing yourself clearly

and eloquently.___ You feel relaxed when writing.___ You like to play with words.___ You enjoy becoming involved with ideas, characters, and

images in your writing.

Version 1 (Intrinsic)

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INSTRUCTIONS: Please rank the following list of reasons for writing, in order of personal importance to you (1=highest, 7=lowest).

___ You want your teachers to be favorably impressed with your writing talent.

___ You enjoy public recognition of your work.___ You know that many of the best jobs available require good

writing skills.___ You know that writing ability is one of the major criteria for

acceptance into graduate school.___ Your teachers and parents have encouraged you to develop

your writing ability.___ You are rewarded in many classes with good grades if you

write well.___ You hope to one day publish your writings and earn money

for your work.

Version 2 (Extrinsic)

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Supposed to convey vivid impression in 17 Japanese characters

Typically 3 lines and 17 syllables (5-7-5)

Give a couple of examples:

Exploring the worldAnd yet never far from home:Snail crosses my path.

She loves these poemsWord pictures, so clear, so sharp:Seductive bullets.

Compose a haiku poem about “statistics”

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General Question: Do reward systems (e.g. grading, incentives at work,

praise for children) produce their desired outcomes?

Specific Research Question: Is there evidence that creativity is affected by the type of

motivation (intrinsic or extrinsic) induced by the questionnaire?

Study Procedures: Subjects: 47 experienced writers Randomization: 2 treatment groups – intrinsic, extrinsic Task: write Haiku poem about “laughter” Data: average creativity score from 12 poet-judges

Discuss study as described in The Statistical Sleuth

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1) Were there any important differences between Amabile’s study and ours?

2) How do we decide if the difference in average creativity between the two groups is “significant”?

3) If the difference is significant, can we conclude that an intrinsic focus caused a temporary increase in creativity?

4) Can we extend these results to reward systems at work and at school?

Thought Questionsat the end of Day One

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Amabile’s subjects: Selected from a pool of volunteers based on advanced

writing courses or hrs/week writing or poems published. Paid $3 for hour. Excluded if over 2 SDs above the mean on any measure

Amabile’s randomization: 3 groups – intrinsic, extrinsic, control “Certain restrictions” – e.g. gender balance, equal mean

and SD for writing involvement pre-scores

1) Were there any important differences between

Amabile’s study and ours?

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Amabile’s study procedures: Intrinsic-extrinsic questionnaire items pre-tested by

Brandeis undergrads Subjects participated individually Haiku-style poems had different structure (5 lines) Wrote initial poem to check on equivalence of creativity

skills All groups read short story after initial poem Experimental groups completed intrinsic/extrinsic

questionnaire after short story (control read longer) Primary poem on theme of “Laughter” Extrinsic group given intrinsic questionnaire to ensure

they had “no long-lasting detrimental effects” Creativity score was sum of ratings by 12 poets

1) Were there any important differences between

Amabile’s study and ours? (continued)

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Amabile reports that creativity is significantly lowered in extrinsic group

We use class data to review two-sample comparisons:

Graphical and numerical summaries Randomization test (new to many) Two-sample t-test and confidence intervals Model assumptions

We’ve never found a significant difference between group in our class data – ask “Why?”

2) How do we decide if the difference in average creativity

between the two groups is “significant”?

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Amabile claims that “creativity may be undermined if extrinsic goals are simply made salient”, while “there is no strong evidence that concentrating on intrinsic reasons for writing caused a temporary increase in creativity.”

We review randomized experiments vs. observational studies

3) If the difference is significant, can we conclude that an intrinsic

focus caused a temporary increase in creativity?

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Amabile writes, “Practically, this research has implications for socialization, educational techniques, and working environments.”

Our class discussion on generalizability issues is often animated and wide-ranging

4) Can we extend these results to reward systems at work and at

school?

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Sharing haiku poems with class Becoming a published poet Cash prizes!!

Final Benefits

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CAUSE A-Mu-sing Contest Winners – Poetry Division -

2009

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World of chaosHow can I find truth in here?Stats gives life order. (by Carolyn Raitt)

Reality bitesWhipping data into shapeStatistics bites back (by Hannah Johnson)

Is it you, or me?Your hopes, my size - both too bigLove, your p-value (by Nicole Villa)

CAUSEweb > Resources > Fun > Poem (direct link), or at www.causeweb.org/cwis/SPT--FullRecord.php?ResourceId=1883

Selected St. Olaf statistics haikus featured on CAUSEweb

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Any questions or suggestions?

Paul RobackSt. Olaf Collegeroback@stolaf.edu

Thanks!