uating the Use of the Savannah Hypothesis among Kenyan Workers and Japanese Students Muruka.doc

evaluating the use of the savannah hypothesis among kenyan workers and japanese studentsandrew oduor murukaa thesis submitted in partial fulfillment for the degree of master of science in occupational safety and health in the jomo kenyatta university of agriculture and technology2012ivdeclarationthis thesis is my original work and has not been presented for a degree in any other university.signature: date: andrew oduor muruka this thesis has been submitted for examination with our approval as university supervisors:1. signature: date: prof. jospeh m. keriko jkuat, kenya2. signature: date: prof. shinji miyakeuniversity of occupational and environmental health, (uoeh), japandedicationthis thesis is dedicated to my beloved daughter, joy quinsley anyango oduor who was born during data analysis.acknowledgementthe preparation of this thesis would not have been possible without the support and help of several persons and especially the 890 respondents who voluntarily participated in my study. their valuable contributions were what made the pages of this thesis come alive. my sincere appreciation is expressed to my kenyan supervisor, professor joseph m. keriko (principal, nairobi campus, jomo kenyatta university of agriculture and technology (jkuat) for not only scrutinizing every word in this thesis but also for his vote of confidence in me and unending support from the beginning to the end of my study. to my special advisor, mentor, teacher and japanese academic supervisor, professor shinji miyake, director of education, department of safety and health management, university of occupational and environmental health, japan, i give special thanks for the words of encouragement and a smile when i needed them most, as well as for his patience, enthusiasm, special interest, technical assistance, expertise and friendly criticisms. i sincerely thank him for directing his and his universitys resources towards the success of this thesis by personally travelling to kenya, his first trip ever to africa. special recognition is due to my family members who gave moral, financial, social support and to my wives, mrs. christine o. muruka and mrs. margaret m. muruka for enduring long periods of psychological and physical absence during the study period. and to my parents, patricia and joanes muruka and all my children: alfred, mary jullienne, ryan dileque junior, prince emmanuel and joy who truly missed me when they needed me most. to prof. fumio yamada, head of department, department of health psychology, school of human sciences, osaka universityofhuman science, japan for his special expertise as an external examiner. i am most grateful to both my bother-in-law, mr. vincent were and brother, mr. steven muruka for assisting in data collection, developing keen interest in my work and supporting my data analysis and to my brother charles muruka and sister joyce muruka for giving invaluable and immeasurable support to my studies. i want to express deep appreciation to my director, mr. p. w. makhonge, director of occupational safety and health services and mr. samuel thuita, for according the time that i needed most to conduct the research work and write my thesis. may comfort be upon them all. a final, but very special, appreciation is directed to god for everything. table of contentsdeclaration. iidedication. iiiacknowledgment.ivtable of contents.vilist of tables.xiv list of figures.xv list of plates.xviii list of appendices. xixabstract. xxchapter 1: introduction and literature review1.1background on savannah ecosystem.11.2the savannah hypothesis.31.3the concept of comfort.71.4indoor work environment quality.91.5 the effects of nature elements and trees on comfort and productivity.91.6savannah hypothesis and most preferred visually attractive tree species .121.7stress at work141.8legal framework on working conditions in kenya.151.8.1the constitution of kenya.1518.2the occupational safety and health act, 2007.161.8.3the factories (noise prevention and control), rules, 2005.161.9 paired comparison method (the law of comparative judgment).171.10conceptual framework.201.11theoretical framework.211.12statement of the problem.261.13significance and justification of the study.271.14research questions.281.15hypotheses.291.16objectives291.16.1main objectives.291.16.2specific objectives.301.17limitations and assumptions of the study.30chapter 2: materials and methods 332.1research sites/areas.332.2research design .342.3study population352.4sampling design.362.4.1kenyan workers.362.4.2respondents from nyakach district, nyanza province, kenya.382.4.3respondents from japan392.5data collection instruments and methods.402.5.1respondent categories.402.5.2workplaces in nairobi.412.5.3primary school teachers in nyakach district, nyanza province, kenya.432.5.4tree species and tree silhouettes canopies selected for the study432.5.5questionnaires .452.5.6pre-testing of questionnaires.482.6data analysis methods.482.6.1conversion of the 5-point rating scale into mean scores.482.6.2student-newman_keuls (s-n-k) analysis of paired comparisons and statistical parameters used in making inferences50 2.6.3multiple comparisons method for significant differences by tukey method with studentized range for analysis of elementary school pupil tree preferences.522.6.4analysis methods for workplace rating.562.6.5rating of feelings about trees and plants in the workplace. 572.6.6comments about plants in the workplace.57chapter 3: results and discussions583.0 results.583.1demographic characteristics of respondents.583.1.1highest educational level.583.1.2age distribution of respondents583.1.3religion of respondents.603.1.4nationality of respondents.603.1.5gender distribution of respondents.603.1.6 residence /dwelling of respondents.613.1.7duration of stay in current residence.613.2analysis of variance (anova) and determination of tree and form preferences613.2.1general linear model repeated measures analysis of variance.613.2.2student -newman-keuls (s-n-k) multiple comparisons623.2.3multiple comparisons for significant differences by tukey method with studentized range643.3religion and tree canopy preferences663.3.1.hindus and tree canopy preferences663.3.2 muslims and tree canopy preferences663.3.3christians and tree canopy preferences673.4 nationality and tree canopy preferences .683.4.1.kenyans tree canopy preferences.683.4.2.japanese tree canopy preferences .703.5 gender and tree canopy preferences.713.5.1kenyan male tree canopy preferences.713.5.2japanese male students tree canopy preferences723.5.3nairobi male employees tree canopy preferences733.5.4nyakach district male teachers tree canopy preferences743.5.5combined male gender tree canopy preferences 753.5.6japanese female tree canopy preferences 763.5.7kenyan female tree canopy preferences773.5.8nairobi female employees tree canopy preferences783.5.9nyakach district female teachers tree canopy preferences.803.5.10. combined female gender tree canopy preferences803.6educational level and tree canopy preferences.813.6.1primary educational level tree canopy preferences813.6.2secondary educational level tree canopy preferences 813.6.3undergraduate educational level tree canopy preferences.823.6.4postgraduate educational level tree preferences.843.7.residence and tree canopy preferences.853.7.1combined urban dwellers tree canopy preferences853.7.2kenyan urban dwellers tree canopy preferences863.7.3rural dwellers tree canopy preferences.873.8age categories and tree canopy preferences.883.8.1age category 1 ( 20 years old) and tree canopy preferences.883.8.2age category 2 (20 - 30 years old) tree canopy preferences893.8.3age category 3 (31 - 40 years old) tree canopy preferences913.8.4age category 4 (41 - 50 years old) tree canopy preferences923.8.5age category 5 (50 + years old) tree canopy preferences.933.9combined overall tree canopy preferences.933.10results of the paired comparison method (pcm) and analysis of variance (anova) of form/context preferences. 943.10.1 form/context preferences .943.10.2 residence/dwelling and form preferences.943.10.2.1urban residence form preferences.943.10.2.2rural residence form preferences.953.11religion and form preferences.963.11.1hindu and form preferences. 973.11.2muslims and form preferences.983.11.3christians and form preferences.993.12age categories and form preferences.1003.12.1age category 1 ( 20 years) form preferences. 1003.12.2age category 2 (20 - 30 years old) form preferences 1013.12.3age category 3 (31 - 40 years old) form preferences. 1023.12.4age category 4 (41 - 50 years old) form preferences. 1033.12.5age category 5 (50 + years old) form preferences 1043.13educational level and form/context preference. 1053.13.1primary educational level form preferences 1053.13.2secondary educational level form preferences. 1063.13.3undergraduate educational level form preferences. 1073.13.4postgraduate educational level form preferences 1083.14gender and form preferences. 1093.14.1female form/context preferences. 1093.14.2male form/context preferences. 1103.15kenyans combined form/context preferences. 1113.16elementary school pupil tree preferences. 1123.16.1 multiple comparisons method for significant differences by tukey method with studentized range. 1123.17rating of workplace conditions. 1163.17.1rating of workplace conditions with respect to noise 1163.17.2rating of workplace conditions with respect to dust 1193.17.3effects of dust on health and well-being 1203.17.4work environment surveys on dust in kenya 1203.17.5individual exposures to dust 1223.17.6rating of workplace conditions with respect to heat 1223.17.7rating of workplace conditions with respect to darkness. 1233.18 summary of comments about plants in the workplace 1263.19discussion 1283.20 tree canopy preferences 1283.20.1implications of savannah hypothesis and the preference for acacia tortilis (acacia), mangifera indica (mango) and cocos nucifera (palm)1283.20.2implications of savannah hypothesis and the preference for euphorbia candelabrum (euphorbia)1363.21preference for potted plants .1363.22.rated workplace conditions.137chapter 4 : conclusions and recommendations. 1394.1summary of findings.1394.1.1the most preferred tree canopy .1394.1.2the most preferred form/context.1394.2conclusions .1394.3recommendations.144references.147appendices.178list of tablestable 2.1:categories of respondents.40table 2.2:workplaces studied in nairobi42table 2.3:rating of working conditions56table 2.4:sample data for general linear model repeated measures anova for 6 hindu respondents.62table 2.5: sample rearrangement of data for student-newman-keuls(s-n-k) multiple comparisons analysis for 2 hindu respondents.63table 2.6:summary on elementary and kindergarten respondents.64table 2.7:initial tabulation of data for multiple comparisons for significant differences by tukey method with studentized range.65table 2.8:summation of response data and average ratio scores of tree silhouettes .113table 2.9:average ratios of tree silhouettes 113table 2.10 :results of stepwise comparisons.115table 2.11: rating of workplace noise conditions in kenyan workplaces117table 2.12: noise as a source of worry.117table 2.13:psychological and physiological effects of noise.118table 2.14:dust in a tea factory.121table 2.15:perceived thermal conditions in kenya.122list of figuresfigure 1.1:comfort in perspective.20figure 2.1:tree silhouettes compared by elementary school pupils47figure 3.1:graphic illustration of muslims tree canopy preferences.67figure 3.2:graphic illustration of christians tree canopy preferences.68figure 3.3:graphic illustration of kenyans tree canopy preferences.69figure 3.4:graphic illustration of japanese tree canopy preferences.70figure 3.5:graphic illustration of kenyan male tree canopy preferences.72figure 3.6:graphical illustration of japanese male students tree preferences73figure 3.7:graphic illustration of nairobi male employees tree preferences.74figure 3.8:combined male gender tree canopy preferences.75figure 3.9:japanese female tree canopy preferences 76figure 3.10:kenyan female tree canopy preferences.78figure 3.11:nairobi female tree canopy preferences.79figure 3.12:combined female tree canopy preferences.80figure 3.13:secondary educational level tree preferences.82figure 3.14:graphic illustration of undergraduate educational level tree canopy preferences.83figure 3.15:graphic illustration of postgraduate educational level tree canopy preferences.84figure 3.16:graphic representation of combined urban dwellers tree canopy preferences .85figure 3.17:graphic illustration of urban kenyans tree canopy preferences.87figure 3.18:graphic illustration of rural dwellers tree canopy preferences.88figure 3.19:graphic illustration of age category 1 (20 years old) tree canopy preferences.89figure 3.20:graphic illustration of age category 2 (20 - 30 years old) tree canopy preferences.90figure 3.21:age category 3 (31 - 40 years old) tree preferences.91figure 3.22: graphic illustration of age category 4 (41 - 50 years old) tree canopy preferences.92figure 3.23:graphic illustration of combined overall tree canopy preferences93figure 3.24:urban residence form preferences.95figure 3.25:rural residence form preferences.96figure 3.26:hindu and form preferences.97figure 3.27:muslims