scholarly journals The t Distribution: A Transformation of the Employee of the Brewery

2014 ◽  
Vol 2 (2) ◽  
Author(s):  
Jorge Mario Insignares Movilla U Insignares Movilla
Keyword(s):  
Hypothesis Testing ◽  
Sample Size ◽  
Normal Distribution ◽  
Detailed Analysis ◽  
Small Sample Size ◽  
Small Sample ◽  
The Other ◽  
Data Set ◽  
Sample Data ◽  
T Distribution

In situations where the size of the sample data set is relatively small, toassume a normal distribution. some uncertainties exist. A mistake is to userandom sampling and the other the small sample size. That is why, beginningwith the story of the generalities that solved the problem t distribution, thenabout topics that support, and …nally, a detailed analysis with some relationshipswith other distributions. While ignore the importance for hypothesis testing instatistical inference when means were contrasted

scholarly journals Fish mislabelling in France: substitution rates and retail types

2014 ◽  
Author(s):  
Julien Bénard-Capelle ◽  
Victoire Guillonneau ◽  
Claire Nouvian ◽  
Nicolas Fournier ◽  
Karine Le Loët ◽  
...  
Keyword(s):  
Natural Resources ◽  
Sample Size ◽  
Citizen Science ◽  
Substitution Rate ◽  
Small Sample Size ◽  
Bluefin Tuna ◽  
Small Sample ◽  
The Other ◽  
Species Substitution ◽  
Scientific Expertise

The development of citizen science has brought together scientific expertise and volunteer involvement to answer both scientific and societal questions. In this study, a consortium of citizens, journalist, scientists and non governmental organisations reports the first measure of the market-wide rate of fish mislabelling in France.We collected in fishmonger shops, supermarkets and restaurants and sequenced 390 samples of fish either in fillets or prepared meals, which is the largest dataset assembled to date in an European country.The overall substitution rate is one of the lowest observed for comparable surveys with large sampling in Europe. Remarkably, we detected no case of species mislabelling among the frozen fillets or in industrially prepared meals. We also investigated most of the mislabelling cases detected directly from the sellers. A number of them admitted that the substitution took place at the end of the supply chain.The rate of mislabelling does not differ between species (3.7 %, ci 2.2-6.4%), except for bluefin tuna. Despite a very small sample size (n=6), this species stands in sharp contrast with the low substitution rate observed for the other species (rate between 36 and 99%). This study shows that even in countries where species substitution rate is low, citizen science can enhance the management of natural resources and provide important insights for regulation policies.

scholarly journals Comparative evaluation of goodness of fit tests for normal distribution using simulation and empirical data

2020 ◽  
Vol 57 (2) ◽  
pp. 237-251
Author(s):  
Achilleas Anastasiou ◽  
Alex Karagrigoriou ◽  
Anastasios Katsileros
Keyword(s):  
Sample Size ◽  
Normal Distribution ◽  
Empirical Data ◽  
Goodness Of Fit ◽  
Small Sample Size ◽  
Small Sample ◽  
Type I ◽  
Sample Sizes ◽  
Omnibus Test ◽  
Wide Range

SummaryThe normal distribution is considered to be one of the most important distributions, with numerous applications in various fields, including the field of agricultural sciences. The purpose of this study is to evaluate the most popular normality tests, comparing the performance in terms of the size (type I error) and the power against a large spectrum of distributions with simulations for various sample sizes and significance levels, as well as through empirical data from agricultural experiments. The simulation results show that the power of all normality tests is low for small sample size, but as the sample size increases, the power increases as well. Also, the results show that the Shapiro–Wilk test is powerful over a wide range of alternative distributions and sample sizes and especially in asymmetric distributions. Moreover the D’Agostino–Pearson Omnibus test is powerful for small sample sizes against symmetric alternative distributions, while the same is true for the Kurtosis test for moderate and large sample sizes.

scholarly journals Autoregressive Prediction with Rolling Mechanism for Time Series Forecasting with Small Sample Size

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Zhihua Wang ◽  
Yongbo Zhang ◽  
Huimin Fu
Keyword(s):  
Time Series ◽  
Sample Size ◽  
Small Sample Size ◽  
Computational Effort ◽  
Small Sample ◽  
Grey Theory ◽  
Data Set ◽  
Rolling Mechanism ◽  
Short Term Forecasting ◽  
Prediction Approach

Reasonable prediction makes significant practical sense to stochastic and unstable time series analysis with small or limited sample size. Motivated by the rolling idea in grey theory and the practical relevance of very short-term forecasting or 1-step-ahead prediction, a novel autoregressive (AR) prediction approach with rolling mechanism is proposed. In the modeling procedure, a new developed AR equation, which can be used to model nonstationary time series, is constructed in each prediction step. Meanwhile, the data window, for the next step ahead forecasting, rolls on by adding the most recent derived prediction result while deleting the first value of the former used sample data set. This rolling mechanism is an efficient technique for its advantages of improved forecasting accuracy, applicability in the case of limited and unstable data situations, and requirement of little computational effort. The general performance, influence of sample size, nonlinearity dynamic mechanism, and significance of the observed trends, as well as innovation variance, are illustrated and verified with Monte Carlo simulations. The proposed methodology is then applied to several practical data sets, including multiple building settlement sequences and two economic series.

scholarly journals -Plot for Testing Spherical Symmetry for High-Dimensional Data with a Small Sample Size

2012 ◽  
Vol 2012 ◽  
pp. 1-18
Author(s):  
Jiajuan Liang
Keyword(s):  
Sample Size ◽  
Spherical Symmetry ◽  
Graphical Method ◽  
Small Sample Size ◽  
High Dimensional Data ◽  
Monte Carlo Study ◽  
Real Data ◽  
Small Sample ◽  
High Dimensional ◽  
Data Set

High-dimensional data with a small sample size, such as microarray data and image data, are commonly encountered in some practical problems for which many variables have to be measured but it is too costly or time consuming to repeat the measurements for many times. Analysis of this kind of data poses a great challenge for statisticians. In this paper, we develop a new graphical method for testing spherical symmetry that is especially suitable for high-dimensional data with small sample size. The new graphical method associated with the local acceptance regions can provide a quick visual perception on the assumption of spherical symmetry. The performance of the new graphical method is demonstrated by a Monte Carlo study and illustrated by a real data set.

scholarly journals Retrospective study of the effectiveness of four different treatments of equine cheek teeth periodontal disease

2016 ◽  
Author(s):  
Kirsten Jackson ◽  
Lukas M. Weber ◽  
Marc Tennant
Keyword(s):  
Periodontal Disease ◽  
Sample Size ◽  
Small Sample Size ◽  
Case Series ◽  
Small Sample ◽  
The Other ◽  
Periodontal Pocket ◽  
Confounding Effect ◽  
Pocket Depth ◽  
Treatment Methods

Reasons for performing the study. Equine cheek teeth periodontal disease is a common, often painful dental condition that may lead to premature tooth loss if left untreated. All cases of periodontal disease in this study were associated with diastemata, with the majority of cases being secondary or senile diastemata. At present limited objective information is available comparing different treatment methods for the condition to assist clinicians in making evidence-based treatment decisions. Objectives. To compare the effectiveness of four commonly used treatments for equine periodontal disease (additional to routine dental treatment and equilibration) to assess their merit in reducing periodontal pocket depth. Study design. Retrospective case series. Methods. Four commonly used equine periodontal treatments were compared: Removing feed material and lavaging the periodontal pocket with dilute chlorhexidine and rinsing the mouth with chlorhexidine based mouthwash (‘Hexarinse’), ‘clean and antiseptic lavage’ (CL); CL plus the addition of metronidazole antibiotics into the periodontal pockets (M); M plus the addition of a polyvinyl siloxane temporary filling over the diastema (PVS); and diastema widening to open the diastema and increase the interdental space between adjacent teeth, then PVS (DW). Periodontal pocket depth measurements were compared before and after treatment at treatment intervals between two and six months. Results. Treatment groups CL, M and PVS showed statistically significant reductions in pocket depth following treatment. Mean pocket depth reduction was greatest in the DW group (and this was the only group with no cases involving an increase in pocket depth), but this was based on a small sample size and was not statistically significant. Additional analysis to compare effectiveness revealed a strong confounding effect of initial pocket depth. After taking this into account, there was some evidence that DW was associated with smaller improvements than the other treatments, however this result was also based on a small sample size, and influenced by a small number of cases with particularly large improvements. Among the other treatments, no statistically significant differences in effectiveness were found. Conclusion. This study has shown that treatment methods CL, M and PVS are associated with statistically significant reductions in pocket depth. Due to the confounding effect of initial pocket depth, no clear differences in effectiveness were found between treatment methods.

scholarly journals A Blended Two-Sided Chain Sampling Plan Created on Process Potential Measure

2021 ◽  
Vol 12 (2) ◽  
pp. 1021-1024
Author(s):  
K. Rebecca Jebaseeli Edna, Et. al.
Keyword(s):  
Sample Size ◽  
Normal Distribution ◽  
Small Sample Size ◽  
Small Sample ◽  
Sampling Plan ◽  
Research Article ◽  
Inspection Plan ◽  
Potential Measure

This research article presents, a blended two-sided chain inspection plan with process potential measure. The Probability of acceptance and related measures are shown. Tables are prepared to find the parameters of the plan. In this plan the variable inspection sample size is obtained by using normal distribution and in the attribute inspection, two-sided chain sampling plan which yields small sample size is used the designed sampling plan is really used in production industries to study the product with respect to the specification measures and to defend the period and charge of inspection to impact on the end product.

scholarly journals Retrospective study of the effectiveness of four different treatments of equine cheek teeth periodontal disease

2016 ◽  
Author(s):  
Kirsten Jackson ◽  
Lukas M. Weber ◽  
Marc Tennant
Keyword(s):  
Periodontal Disease ◽  
Sample Size ◽  
Small Sample Size ◽  
Case Series ◽  
Small Sample ◽  
The Other ◽  
Periodontal Pocket ◽  
Confounding Effect ◽  
Pocket Depth ◽  
Treatment Methods

Reasons for performing the study. Equine cheek teeth periodontal disease is a common, often painful dental condition that may lead to premature tooth loss if left untreated. All cases of periodontal disease in this study were associated with diastemata, with the majority of cases being secondary or senile diastemata. At present limited objective information is available comparing different treatment methods for the condition to assist clinicians in making evidence-based treatment decisions. Objectives. To compare the effectiveness of four commonly used treatments for equine periodontal disease (additional to routine dental treatment and equilibration) to assess their merit in reducing periodontal pocket depth. Study design. Retrospective case series. Methods. Four commonly used equine periodontal treatments were compared: Removing feed material and lavaging the periodontal pocket with dilute chlorhexidine and rinsing the mouth with chlorhexidine based mouthwash (‘Hexarinse’), ‘clean and antiseptic lavage’ (CL); CL plus the addition of metronidazole antibiotics into the periodontal pockets (M); M plus the addition of a polyvinyl siloxane temporary filling over the diastema (PVS); and diastema widening to open the diastema and increase the interdental space between adjacent teeth, then PVS (DW). Periodontal pocket depth measurements were compared before and after treatment at treatment intervals between two and six months. Results. Treatment groups CL, M and PVS showed statistically significant reductions in pocket depth following treatment. Mean pocket depth reduction was greatest in the DW group (and this was the only group with no cases involving an increase in pocket depth), but this was based on a small sample size and was not statistically significant. Additional analysis to compare effectiveness revealed a strong confounding effect of initial pocket depth. After taking this into account, there was some evidence that DW was associated with smaller improvements than the other treatments, however this result was also based on a small sample size, and influenced by a small number of cases with particularly large improvements. Among the other treatments, no statistically significant differences in effectiveness were found. Conclusion. This study has shown that treatment methods CL, M and PVS are associated with statistically significant reductions in pocket depth. Due to the confounding effect of initial pocket depth, no clear differences in effectiveness were found between treatment methods.

scholarly journals Detection of Non-Normality in Data Sets and Comparison between Different Normality Tests

2020 ◽  
pp. 1-20 ◽  
Author(s):  
Biu O. Emmanuel ◽  
Nwakuya T. Maureen ◽  
Nduka Wonu
Keyword(s):  
Sample Size ◽  
Normal Distribution ◽  
Small Sample ◽  
Data Sets ◽  
Normality Test ◽  
Sample Data ◽  
Kolmogorov Smirnov ◽  
Level Of Significance ◽  
Ks Test ◽  
Test For Normality

The paper provides five tests of data normality at different sample sizes. The tests are the Shapiro-Wilk (SW) test, Anderson-Darling (AD) test, Kolmogorov-Smirnov (KS) test, Ryan-Joiner (RJ) test, and Jarque-Bera (JB) test. These tests were used to test for normality for two secondary data sets with sample size (155) for large and (40) for small; and then test the simulated scenario with standard normal “N(0,1)” data sets; where the large samples of sizes (150, 140, 130, 130, 110 and 100) and small samples of sizes (40. 35, 30, 25, 20, 15 and 10) are considered at two levels of significance (5% and 10%). However, the aim of this paper is to detect and compare the performance of the different normality tests considered. The normality test results shows Kolmogorov-Smirnov (KS) test is a most powerful test than other tests since it detect the simulated large sample data sets do not follow a normal distribution at 5%, while for small sample sizes at 5% level of significance; the results showed the Jarque-Bera (JB) test is a most powerful test than other tests since it detects that the simulated small sample data do not follow a normal distribution at 5%. This paper recommended JB test for normality test when the sample size is small and KS test when the sample size is large at 5% level of significance.

scholarly journals Fish mislabelling in France: substitution rates and retail types

2014 ◽  
Author(s):  
Julien Bénard-Capelle ◽  
Victoire Guillonneau ◽  
Claire Nouvian ◽  
Nicolas Fournier ◽  
Karine Le Loët ◽  
...  
Keyword(s):  
Natural Resources ◽  
Sample Size ◽  
Citizen Science ◽  
Substitution Rate ◽  
Small Sample Size ◽  
Bluefin Tuna ◽  
Small Sample ◽  
The Other ◽  
Species Substitution ◽  
Scientific Expertise

The development of citizen science has brought together scientific expertise and volunteer involvement to answer both scientific and societal questions. In this study, a consortium of citizens, journalist, scientists and non governmental organisations reports the first measure of the market-wide rate of fish mislabelling in France.We collected in fishmonger shops, supermarkets and restaurants and sequenced 390 samples of fish either in fillets or prepared meals, which is the largest dataset assembled to date in an European country.The overall substitution rate is one of the lowest observed for comparable surveys with large sampling in Europe. Remarkably, we detected no case of species mislabelling among the frozen fillets or in industrially prepared meals. We also investigated most of the mislabelling cases detected directly from the sellers. A number of them admitted that the substitution took place at the end of the supply chain.The rate of mislabelling does not differ between species (3.7 %, ci 2.2-6.4%), except for bluefin tuna. Despite a very small sample size (n=6), this species stands in sharp contrast with the low substitution rate observed for the other species (rate between 36 and 99%). This study shows that even in countries where species substitution rate is low, citizen science can enhance the management of natural resources and provide important insights for regulation policies.

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