Testing for One-Way ANOVA

Answer

PART ONE

Examination of the one-way ANOVA based on a research question.

Data set used: Afrobarometer

Research question: Do perceptions about future levels of democracy vary depending on country of origin of respondents?

Dependent variable: perceptions about level of democracy in the future (measured on a continuous scale)

Independent variable: country of origin (measured on a nominal scale)

Analysis

Description of results

Results from the ANOVA table indicate that there is a statistically significant difference in the mean level of future  perceptions regarding democracy between the four different countries of origin of the respondents 95%, p <0.05. This table does not tell what specific groups differed, and that information is generated by post hoc tests (Frankfort-Nachmias, C., & Leon-Guerrero, 2015).

The multiple comparison table giving post hoc results indicate that there is a statistically significant difference in perceptions about future democracy between west Africa and east Africa (p = 0.000), between west Africa and Southern Africa (p=0.004), between East Africa and North Africa (p=0.004) and North Africa and Southern Africa (p=0.035). However there was no difference between East Africa and Southern Africa as well as West Africa and Southern Africa. For these two groups p> 0.05.

In general, there was a statistically significant difference between the countries of origin in terms of perceptions about future level of democracy as determined by one-way ANOVA F (3, 45976)  = 7.968, p = 0.000.  A turkey post hoc test revealed that perceptions about future democracy level was statistically significantly lower in East Africa 8.93 (2.057), p=0.000 and in Southern Africa, 8.97(2.059) compared to West Africa 1.945(1.945); significantly higher in North Africa 9.05(2.160), p=0.004 and in West Africa 9.04(1.945), p=0.004 compared East Africa 8.93 (2.057).

Implication of social change

Differences in perception regarding democracy in future call for a more targeted approach with social change intervention, so that regardless of origin, there is an overall positive perception of future democracy.

PART TWO: Article critique

Article Selected:

Lupu, I., & Grosu, M. (2016). Influence of Technological Parameters on Agrotextiles Water Absorbency using ANOVA Model. Annals Of The University Of Oradea: Fascicle Of Textiles, Leatherwork, Vol XVII, Iss 2, Pp 87-92 (2016), (2), 87.

The Author’s Purpose, Approach or Methods, Hypothesis, and Major Conclusions:

In this article the researchers examine the role agrotextiles play in agriculture. The purpose of the study was to examine the water absorptive capacity of needle-punched  nonwoven used as irrigation substrates in agriculture, by analyzing the influence of needle process parameters on absorptive capacity using ANOVA.  The needle process parameters that are examined are frequency of needle board and needle depth penetration. The study demonstrates that there is a significant influence of needling parameters on water absorbent capacity of the agrotextile.

Critique

Methods      

Why did the authors use this one-way ANOVA test?

The authors use one-way ANOVA because they wanted to see if there is difference in water mean absorptive capacity of the agrotextile for frequency of needle board and needle depth penetration

Do you think it’s the most appropriate choice? Why or why not?

The one-way ANOVA was not an appropriate choice. The objective of the study was to examine the influence of frequency of needle board, and needle depth penetration on water absorptive capacity of an agrotextile. ANOVA checks existence of differences between groups. All the variables in this study: the two independent variables namely frequency of needle board, and needle depth penetration as well as the dependent variable namely water absorptive capacity are measured on a numerical scale. The most appropriate test would have been Multiple Linear Regression, so as to come up with a regression model explaining the relationships between the variables.

One of the assumptions of ANOVA test is that the independent variable is measured on a categorical scale and the dependent variable is measured on a numerical scale, so that differences in means of the dependent variable based on the different groups can be examined (Frankfort-Nachmias & Leon-Guerrero 2015). Based on this, a one-way ANOVA is not an appropriate test, because it is not congruent with the study objective and the data collected do not fit the assumptions of ANOVA.

Did the authors display the data?

Yes the data is displayed in tables and graphs

Does the results table stand-alone (i.e., are you able to interpret the study from it?) Why or why not? Yes, the results tables are very informative as they give sufficient information to interpret the findings, even without reading the entire paper.