Power Analysis, Sample Size, and Assessment of Statistical Assumptions—Improving the Evidential Value of Lighting Research

Uttley, Jim

doi:10.1080/15502724.2018.1533851

Cited by 133 publications

(95 citation statements)

References 67 publications

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“…It was first necessary to evaluate the statistical power and the statistical assumptions, as requested in social sciences and lighting research (Uttley 2019). To this end, the sample size and the power of the study were analyzed using the G*Power software, yielding a power over 0.80, calculated as a priori type of power analysis for F testslinear multiple regression for the five analyzed predictors (i.e.…”

Section: Analysis Strategymentioning

confidence: 99%

Window Size Effects on Subjective Impressions of Daylit Spaces: Indoor Studies at High Latitudes Using Virtual Reality

Moscoso

Chamilothori

Wienold

et al. 2020

LEUKOS

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Daylight provision to the indoor space is affected by different building elements that cannot be fully controlled by the users, such as the window size of a space. The dimensions of the fenestration not only affect the lighting levels, but they also affect how the space is perceived by its users. The present study examines three different window sizes via virtual reality, to study how they affect the perception of both a small and a large space at high latitudes. Additionally, two context scenarios (socializing and working), as well as three different sky types (overcast sky and clear skies with either high or low sun angle) were evaluated. The experimental study applied a mixed design with within-subjects and between-subjects factors. A total of 150 participants evaluated the scenes using a Likert-type scale to rate eight different subjective attributes. The statistical results showed that both window size and space type significantly affect the participants' spatial perception, as well as their satisfaction with the amount of outside view. Larger windows led to more positively evaluated spaces for all studied attributes. Moreover, a significant interaction was found between window size and type of space for the satisfaction with the amount of view in the space, indicating that the window size was dependent on the type of space in which the windows are located. Specifically, the window sizes were rated higher in the small space than in the large space for the evaluation of amount of view. The findings show that window size affects how people perceive a space, and additionally, that other spatial features, such as space type, affect window size preferences.

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Section: Analysis Strategymentioning

confidence: 99%

Window Size Effects on Subjective Impressions of Daylit Spaces: Indoor Studies at High Latitudes Using Virtual Reality

Moscoso

Chamilothori

Wienold

et al. 2020

LEUKOS

View full text Add to dashboard Cite

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“…The design of the experiment was therefore informed by a power analysis to detect a 10% effect. This is a novel approach to agronomic biofortification studies; typically, studies on maize (and other crops) have limited replication and therefore limited power to detect small effect sizes (Button et al., 2013; Lark et al., 2020; Uttley, 2019). A second objective is to determine how the effectiveness of agronomic biofortification will differ between Lixisols and Vertisols, with maize grown on Vertisols expected to have higher baseline grain Zn concentrations (Chilimba et al., 2011).…”

Section: Introductionmentioning

confidence: 99%

Increasing zinc concentration in maize grown under contrasting soil types in Malawi through agronomic biofortification: Trial protocol for a field experiment to detect small effect sizes

et al. 2020

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The prevalence of micronutrient deficiencies including zinc (Zn) is widespread in Malawi, especially among poor and marginalized rural populations. This is due to low concentrations of Zn in most staple cereal crops and limited consumption of animal source foods. The Zn concentration of cereal grain can be increased through application of Zn‐enriched fertilizers; a process termed agronomic biofortification or agro‐fortification. This trial protocol describes a field experiment which aims to assess the potential of agronomic biofortification to improve the grain Zn concentration of maize, the predominant staple crop of Malawi. The hypotheses of the study are that application of Zn‐enriched fertilizers will create a relatively small increase in the concentration of Zn in maize grains that will be sufficient to benefit dietary supplies of Zn, and that the effectiveness of agronomic biofortification will differ between soil types. The study will be conducted at three sites, Chitedze, Chitala, and Ngabu Agricultural Research Stations, in Lilongwe, Salima, and Chikwawa Districts respectively. These three sites represent locations in the Central and Southern Regions of Malawi. At each site, two different sub‐sites will be used, each corresponding to one of two agriculturally important soil types of Malawi, Lixisols, and Vertisols. Within each sub‐site, three Zn fertilizer rates (1, 30, and 90 kg/ha) will be applied to experimental plots using standard soil application methods, in a randomized complete block design. The number of replicates at plot level has been informed by a power analysis from pilot study data, assuming that a minimum 10% increase in Zn concentration of grain at 90 kg/ha relative to the concentration at 1 kg/ha is of interest. Grain mass (yield), stover mass, and both stover and grain Zn concentrations will be measured at harvest. A second year of cropping will be used to establish whether there are any residual benefits to grain Zn concentration. The potential for Zn agronomic biofortification will be communicated to relevant academic and government stakeholders through a peer review journal article and a briefing paper.

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“…Afterwards, ten (10) respondents (Solar PV adopters) were selected from each locality, thus giving a total of 200 respondents. This number was appropriate for this kind of study because a recent review paper suggested that the average sample size for lighting (energy) publications is 40 [40]. For most studies on energy, the selected respondents answered questions on behalf of the sampled participating households/houses identified.…”

Section: Sampling Of the Study Sitesmentioning

confidence: 99%

“…See Figure 1 for location of the study sites. average sample size for lighting (energy) publications is 40 [40]. For most studies on energy, the selected respondents answered questions on behalf of the sampled participating households/houses identified.…”

Section: Sampling Of the Study Sitesmentioning

confidence: 99%

Not There Yet: Mapping Inhibitions to Solar Energy Utilisation by Households in African Informal Urban Neighbourhoods

2020

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The average household access to electricity in Nigeria is estimated at four hours per day. This paradoxical energy crisis in a top oil and gas exporting country makes an interesting case for local and global players in the sustainable energy agenda. The current study showcases experiences of households that installed and use solar photovoltaic (PV) technologies in urban Africa. It identifies the key sociotechnical transition issues that shape the households’ solar energy adoption strategies. To get a clear picture of the situation, the study focuses on the Kano urban agglomeration—a densely populated city with high economic activities. To answer the research question, the sampled respondents shared their experiences via questionnaire and interviews. Similarly, field observations guided the research team to identify patterns of household solar energy use, and how urban planning, building, and roofing types inhibit solar energy utilisation. From the results of the study, it appeared that households use solar energy for lighting, energising rechargeable appliances, and cooling of houses. Nevertheless, none of the respondents use solar photovoltaics (PVs) for cooking—the biggest consumer of fuelwood in Nigeria. Finally, this study is optimistic that despite the challenges identified, the transition to clean energy security in Africa is achievable through coordinated efforts of people, industry, and governments. The transition to renewables by households promises significant changes that can lever the mainstreaming of the UN Sustainable Development Goals-SDG no. 7.

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Power Analysis, Sample Size, and Assessment of Statistical Assumptions—Improving the Evidential Value of Lighting Research

Cited by 133 publications

References 67 publications

Window Size Effects on Subjective Impressions of Daylit Spaces: Indoor Studies at High Latitudes Using Virtual Reality

Window Size Effects on Subjective Impressions of Daylit Spaces: Indoor Studies at High Latitudes Using Virtual Reality

Increasing zinc concentration in maize grown under contrasting soil types in Malawi through agronomic biofortification: Trial protocol for a field experiment to detect small effect sizes

Not There Yet: Mapping Inhibitions to Solar Energy Utilisation by Households in African Informal Urban Neighbourhoods

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