Basic Statistical Analyses using R

2021 ◽  
pp. 103-138
Author(s):  
Justin C. Touchon
Keyword(s):  
Statistical Analysis ◽  
Analysis Of Variance ◽  
Statistical Analyses ◽  
Model Fit ◽  
Summary Statistics ◽  
P Values ◽  
Parametric Statistics ◽  
Post Hoc ◽  
Different Levels ◽  
Single Predictor

What are normal data? What are non-normal data? How do you tell them apart and how do you know what sort of data you have? Chapter 5 begins teaching statistical analysis with a focus on understanding the shape of one’s data and how to measure it. The RxP dataset is explored and the principal focus in this chapter is on normal data and on conducting an Analysis of Variance (ANOVA), although classic non-parametric statistics such as a Kruskal-Wallis test and Mann-Whitney U test are also introduced. Readers are taught how to test for data normality, assess model fit, interpret the summary output from the model, calculate summary statistics and p-values, and how to conduct post-hoc tests (Tukey’s HSD) to compare different levels of a single predictor.

scholarly journals Cytotoxicity of bracket identification dyes

2018 ◽  
Vol 89 (3) ◽  
pp. 426-431
Author(s):  
Fatih Celebi ◽  
Ahmet Altun ◽  
Ali Altug Bicakci
Keyword(s):  
Statistical Analysis ◽  
Real Time ◽  
Analysis Of Variance ◽  
Alternative Methods ◽  
Cell Analysis ◽  
Fixed Appliances ◽  
Analysis System ◽  
Post Hoc ◽  
Different Levels

ABSTRACT Objectives: To investigate the potential cytotoxicity of the bracket identification dyes commonly used in orthodontic fixed appliances. Materials and Methods: Six bracket brands representing the market in various aspects were selected. Ten sets of each bracket brand were acquired, and the identification dyes on them were scraped. They were tested for cytotoxicity at three different levels of concentration (2.5 mg/mL, 5 mg/mL, and 10 mg/mL), with the aid of a real-time cell analysis system. The results were compared within and between the groups. One-way analysis of variance and Tukey's post hoc test were used for statistical analysis. Results: None of the six investigated dyes displayed cytotoxicity at the 2.5 mg/mL concentration. Of the investigated brands, three at 5 mg/mL and four at 10 mg/mL displayed cytotoxicity. Conclusions: Some of the identification dyes in this study did display cytotoxicity at the higher concentrations tested. Alternative methods for bracket identification should be considered.

scholarly journals Characteristics of anteroposterior curvatures of the spine in soccer and futsal players

2017 ◽  
Vol 18 (4) ◽  
Author(s):  
Krystyna Chromik ◽  
Anna Burdukiewicz ◽  
Jadwiga Pietraszewska ◽  
Aleksandra Stachoń ◽  
Paweł Wolański ◽  
...  
Keyword(s):  
College Students ◽  
Statistical Analysis ◽  
Injury Prevention ◽  
Analysis Of Variance ◽  
Statistical Significance ◽  
Body Posture ◽  
Soccer Players ◽  
Prevention Training ◽  
The Difference ◽  
Post Hoc

AbstractPurpose. The aim of the study was to determine differences in anteroposterior spine curvatures between futsal players, soccer players, and non-training students. The results may contribute to the development of present-day knowledge of posturometry, and its implementation in training can help reduce the risk of body posture disorders in athletes. Methods. The examined group consisted of 48 athletes and 38 non-training college students. Body posture parameters were measured with the use of Posturometr-S. The normality of distribution was checked with the Shapiro-Wilk test, and the differences between the groups were measured with ANOVA and the Bonferroni post-hoc test. The level of statistical significance was set at p < 0.05. Results. The analysis of angle values revealed the widest and most similar measurements in the group of futsal players and soccer players. The analysis of variance proved statistically significant differences between the soccer players and futsal players (p = 0.003). The difference between the soccer players and non-training students was statistically significant. The highest γ angular value was measured in non-training students, followed by futsal players and soccer players. The statistical analysis revealed significant differences between the non-training students and futsal players, as well as non-training students and soccer players (p < 0.001). Conclusions. A complex assessment of athletes’ body posture is crucial in injury prevention. Training overloads may often lead to disorders of the organ of locomotion and affect the correct body posture in athletes. This, in turn, may result in pains and injuries.

scholarly journals When ANOVA Isn't Ideal: Analyzing Ordinal Data from Practical Work in Biology

2020 ◽  
Vol 82 (5) ◽  
pp. 289-294
Author(s):  
Michael Calver ◽  
Douglas Fletcher
Keyword(s):  
Analysis Of Variance ◽  
Ordinal Data ◽  
Nonparametric Statistics ◽  
Biological Data ◽  
Statistical Analyses ◽  
Practical Work ◽  
Parametric Statistics ◽  
Critical Requirement ◽  
Size Interval ◽  
Biology Laboratory

Data collected in many biology laboratory classes are on ratio or interval scales where the size interval between adjacent units on the scale is constant, which is a critical requirement for analysis with parametric statistics such as t-tests or analysis of variance. In other cases, such as ratings of disease or behavior, data are collected on ordinal scales in which observations are placed in a sequence but the intervals between adjacent observations are not necessarily equal. These data can only be interpreted in terms of their order, not in terms of the differences between adjacent points. They are unsuitable for parametric statistical analyses and require a rank-based approach using nonparametric statistics. We describe an application of one such approach, the Kruskal-Wallis test, to biological data using online freeware suitable for classroom settings.

Using Summary Statistics as Data in ANOVA: A SYSTAT Macro

1991 ◽  
Vol 18 (4) ◽  
pp. 249-251 ◽  
Author(s):  
John F. Walsh
Keyword(s):  
Analysis Of Variance ◽  
Sufficient Information ◽  
Summary Statistics ◽  
Research Findings ◽  
Standard Deviations ◽  
Post Hoc

In laboratory and classroom assignments, students are asked to review research findings. Often the data available include only the means, standard deviations, and number of subjects. A SYSTAT macro is given that generates sufficient information from the data available to compute an analysis of variance (ANOVA) and post hoc analyses.

Determining the Levels of Urbanization in Iran Using Hierar-chical Clustering

2020 ◽  
Author(s):  
Mostafa ENAYATRAD ◽  
Parvin YAVARI ◽  
Koorosh ETEMAD ◽  
Sohila KHODAKARIM ◽  
Sepideh MAHDAVI
Keyword(s):  
Statistical Analysis ◽  
Hierarchical Clustering ◽  
Analysis Of Variance ◽  
Euclidean Distance ◽  
The Other ◽  
Process Of Urbanization ◽  
Four Levels ◽  
To Come ◽  
South Khorasan ◽  
Different Levels

Background: In this study, we used a variety of factors that affect urbanization in Iran to evaluate different provinces in Iran in terms of the level of urbanization. Methods: Using information from census 2011, we collected data on 33 indicators related to urbanization in 31 provinces in Iran. To rank the provinces we used density-based hierarchical clustering scheme. To determine similarities or differences between the provinces, the square of the Euclidean distance dissimilarity coefficient; Ward’s algorithm was used to merge the provinces to minimize intra-cluster variance. One-way analysis of variance (ANOVA) was used to determine the variance between the variables used to rank the provinces in terms of different levels of urbanization. Statistical analysis was performed using SPSS. Results: The provinces in Iran were combined with each other in 30 stages and classified into four levels. Taking into account the variables used to rank the level of urbanization, Tehran, and Alborz provinces were at the highest level of urbanization. On the other hand, the provinces of Sistan and Baluchistan, Kerman, North Khorasan, South Khorasan, Hormozgan, and Bushehr were at the lowest level of urbanization. Conclusion: Identification of provinces at the same level of urbanization can help us to discover the strengths and weaknesses in the infrastructures of each of them. Given the differences between various levels of urbanization, the identification of factors that are effective in the process of urbanization can help to access more information required for designing plans for the years to come.

Dried potato products for egg production: statistical analysis of a laying experiment

1945 ◽  
Vol 35 (3) ◽  
pp. 158-162 ◽  
Author(s):  
W. Bolton ◽  
R. W. Hale
Keyword(s):  
Statistical Analysis ◽  
Approximate Method ◽  
Analysis Of Variance ◽  
Egg Production ◽  
Live Weight ◽  
Statistical Analyses ◽  
Standard Errors ◽  
Experimental Feeding ◽  
The Mean ◽  
Potato Products

An experiment involving twelve pens of twenty-five pullets demonstrated that two types of dried potatoes compared favourably with cereals, as regards their effects on egg production, when up to 42½% of each product was included in the mash.The records of the experiment, as regards (a) the number of eggs laid in 12 months, (b) the mean weight of eggs during the year, and (c) the change in live weight during the year, were studied by analysis of variance, using the approximate method of Yates (1933) for obtaining standard errors of pen means from the variance within pens. Similar analyses of the number of eggs laid in the month were carried out for each month separately. The latter analyses indicated the months in which increased production was obtained from the superior rations, and showed that duplicate pens had reacted similarly to the experimental feeding. The results of the statistical analyses are set out in some detail as an example of method.

scholarly journals Mindfulness and burnout among competitive adolescent tennis players

2013 ◽  
Vol 25 (4) ◽  
pp. 105
Author(s):  
SP Walker
Keyword(s):  
Multivariate Analysis ◽  
Protective Effect ◽  
Analysis Of Variance ◽  
Adolescent Athletes ◽  
Tennis Players ◽  
Intrapersonal Factors ◽  
Athlete Burnout ◽  
Post Hoc ◽  
The Relationship ◽  
Different Levels

Background. Burnout among adolescent athletes is a cause for concern. However, little is known about the intrapersonal factors that may be related to burnout in this population.Objectives. To explore the relationship between burnout and mindfulness among competitive adolescent tennis players.Methods. Competitive adolescent tennis players (N=104; mean age 16 years) completed measures of mindfulness and athlete burnout. Correlations were calculated with regard to mindfulness and burnout. A one-way multivariate analysis of variance (MANOVA) was conducted to determine whether athletes assigned to three levels of mindfulness (high, moderate and low) differed significantly with regard to burnout.Results. Mindfulness exhibited significant negative correlations with global burnout, emotional/physical exhaustion, reduced sense of accomplishment and sport devaluation. The results of the MANOVA indicated that individuals in the three mindfulness groups (high, moderate and low) reported significantly different levels of burnout. Post hoc analyses revealed that participants in the high mindfulness group reported a significantly lower sense of reduced accomplishment and global burnout than participants in the low mindfulness group. In addition, participants in the low mindfulness group reported significantly higher levels of global burnout than individuals in the high and moderate mindfulness groups.Conclusion. Mindfulness appears to be negatively related to athlete burnout among competitive adolescent tennis players. Furthermore, athletes reporting different levels of mindfulness exhibit differing levels of burnout. The potential protective effect of mindfulness with regard to burnout among adolescent athletes warrants further investigation.

scholarly journals Statistical Analysis of Leading Goal Scoring Pattern of Europe’s Top Five Football Leagues

2020 ◽  
Vol 9 (4) ◽  
pp. 517-521
Keyword(s):  
Statistical Analysis ◽  
Analysis Of Variance ◽  
P Value ◽  
Microsoft Excel ◽  
Post Hoc Analysis ◽  
Premier League ◽  
European Football ◽  
Post Hoc ◽  
The Relationship ◽  
Frequency Counts

Previous researchers have discussed goal-scoring patterns of different football leagues, but little has been done on leading or top goal scorer. In this study, the focus is on the relationship between leading goal scoring and final league position for the top five European leagues (Premier League, La Liga, Serie A, Bundesliga and Ligue 1). The five leagues are the current top leagues in Europe as ranked by the Union of European Football Association (UEFA). The data were obtained from the respective leagues’ football association websites. The data were entered into Microsoft Excel spreadsheet to create frequency counts. Thereafter correlation and analysis of variance (ANOVA) was done using Minitab 18.0 and SPSS version 23. From the result, it was observed that there is a significant relationship between leading goal scoring and league positions for La Liga at a p value equals 0.013 and Germany at a p value equals 0.042, but no relationship for the remaining three leagues. Choosing the last 20 seasons only, the analysis of variance (ANOVA) revealed that the final league positions of the clubs that produced the leading goal scorers are the same across the leagues at p value = 0.349. However, the opposite is the case of the goal-scoring pattern and p value < 0.005 were obtained. Further investigation using the Post Hoc analysis revealed that the goal-scoring pattern of leading goal scores in Spanish La Liga is significantly different from others.

scholarly journals Mindfulness and burnout among competitive adolescent tennis players

2013 ◽  
Vol 25 (4) ◽  
pp. 105 ◽  
Author(s):  
SP Walker
Keyword(s):  
Multivariate Analysis ◽  
Protective Effect ◽  
Analysis Of Variance ◽  
Adolescent Athletes ◽  
Tennis Players ◽  
Intrapersonal Factors ◽  
Athlete Burnout ◽  
Post Hoc ◽  
The Relationship ◽  
Different Levels

Background. Burnout among adolescent athletes is a cause for concern. However, little is known about the intrapersonal factors that may be related to burnout in this population.Objectives. To explore the relationship between burnout and mindfulness among competitive adolescent tennis players.Methods. Competitive adolescent tennis players (N=104; mean age 16 years) completed measures of mindfulness and athlete burnout. Correlations were calculated with regard to mindfulness and burnout. A one-way multivariate analysis of variance (MANOVA) was conducted to determine whether athletes assigned to three levels of mindfulness (high, moderate and low) differed significantly with regard to burnout.Results. Mindfulness exhibited significant negative correlations with global burnout, emotional/physical exhaustion, reduced sense of accomplishment and sport devaluation. The results of the MANOVA indicated that individuals in the three mindfulness groups (high, moderate and low) reported significantly different levels of burnout. Post hoc analyses revealed that participants in the high mindfulness group reported a significantly lower sense of reduced accomplishment and global burnout than participants in the low mindfulness group. In addition, participants in the low mindfulness group reported significantly higher levels of global burnout than individuals in the high and moderate mindfulness groups.Conclusion. Mindfulness appears to be negatively related to athlete burnout among competitive adolescent tennis players. Furthermore, athletes reporting different levels of mindfulness exhibit differing levels of burnout. The potential protective effect of mindfulness with regard to burnout among adolescent athletes warrants further investigation.

scholarly journals Evaluation of Disclusion Time in Various Angle’s Malocclusions by T-Scan III System

2019 ◽  
Vol 13 (04) ◽  
pp. 510-513
Author(s):  
Titirat Chutchalermpan ◽  
Jittima Pumklin ◽  
Thosapol Piyapattamin
Keyword(s):  
Statistical Analysis ◽  
Analysis Of Variance ◽  
Numerical Data ◽  
Class Ii ◽  
Class I ◽  
Class Iii ◽  
Division 1 ◽  
Standard Deviations ◽  
Post Hoc ◽  
Division 2

Abstract Objective The main purpose of this article is to evaluate the disclusion time (DT) in the lateral excursions and protrusion among subjects with Angle’s malocclusions using a T-Scan III system. Materials and Methods One hundred subjects with malocclusions were divided into Class I, Class II division 1, Class II division 2, and Class III (n = 25 per group). All groups’ DT of each excursion was evaluated by a T-Scan III system. Statistical Analysis One-way analysis of variance, followed by a post hoc test, was used to analyze the numerical data at p < 0.05. Results In the respective malocclusions, means ± standard deviations in second(s) of the DT were 2.08 ± 0.65, 2.13 ± 0.74, 2.12 ± 0.72, and 3.19 ± 1.34 during left excursion; 2.15 ± 0.94, 2.58 ± 1.16, 2.37 ± 1.07, and 3.28 ± 1.25 during right excursion; and 1.88 ± 0.99, 2.08 ± 1.11, 2.07 ± 0.68, and 3.01 ± 1.53 during protrusion. When compared to Class I and Class II malocclusions, Class III showed a significantly higher mean DT of each excursion (p < 0.05). Conclusion Class III had the significantly highest mean DT of each excursion and the significantly longest DT in all excursions.

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