Statistical Analysis Relating to Recent Federal Standard 209 (Cleanrooms) Revisions

1988 ◽  
Vol 31 (5) ◽  
pp. 48-52
Author(s):  
Douglas Cooper
Keyword(s):  
Standard Deviation ◽  
Statistical Tests ◽  
Average Concentration ◽  
Airborne Particles ◽  
Simulation Methods ◽  
Concentration Data ◽  
Normal Distributions ◽  
Good Practices ◽  
Federal Standard ◽  
Poisson Data

The recent revisions of Federal Standard 209 regarding clean-rooms include two statistical tests for the concentration data obtained from sampling airborne particles: a) that none of the location averages exceeds the Class Limit (CL) and b) that there be 95 percent confidence that the true mean of the location averages does not exceed the CL, based on the data making up the grand mean of averages. For sampling from a constant and uniform concentration (Poisson data) or from a concentration giving data that are normally distributed, we show the statistical implications of choosing a certain level of confidence that no location average exceed CL. Similarly, we show the statistical implications of the 95 percent confidence requirement on the grand mean. For any situation where each location has approximately the same standard deviation in its readings, the Poisson and normal distributions included, if one has 95 percent confidence that none of the locations exceeds the CL, the requirement for the grand mean is also likely to be met if five or more locations are sampled. Simulation methods can assist prediction, and several methods are summarized. The likelihood of meeting the standard can usually be improved by: reducing the average concentration and the variability of the concentration (through design and good practices), increasing the number of samples per location and the volume sampled for each, and keeping the number of locations sampled to the minimum allowed.

Statistical Analysis Relating to Recent Federal Standard 209 (Cleanrooms) Revisions

1988 ◽  
Vol 31 (2) ◽  
pp. 32-36
Author(s):  
Douglas Cooper
Keyword(s):  
Standard Deviation ◽  
Statistical Tests ◽  
Average Concentration ◽  
Airborne Particles ◽  
Simulation Methods ◽  
Concentration Data ◽  
Normal Distributions ◽  
Good Practices ◽  
Federal Standard ◽  
Poisson Data

The recent revisions of Federal Standard 209 regarding clean-rooms include two statistical tests for the concentration data obtained from sampling airborne particles: a) that none of the location averages exceeds the Class Limit (CL) and b) that there be 95 percent confidence that the true mean of the location averages does not exceed the CL, based on the data making up the grand mean of averages. For sampling from a constant and uniform concentration (Poisson data) or from a concentration giving data that are normally distributed, we show the statistical implications of choosing a certain level of confidence that no location average exceed CL. Similarly, we show the statistical implications of the 95 percent confidence requirement on the grand mean. For any situation where each location has approximately the same standard deviation in its readings, the Poisson and normal distributions included, if one has 95 percent confidence 'that none of the locations exceeds the CL, the requirement for the grand mean is also likely to be met if five or more locations are sampled. Simulation methods can assist prediction, and several methods are summarized. The likelihood of meeting the standard can usually be improved by: reducing the average concentration and the variability of the concentration (through design and good practices), increasing the number of samples per location and the volume sampled for each, and keeping the number of locations sampled to the minimum allowed.

Weighted Simplex Procedures for Determining Boundary Points and Constants for the Univariate and Multivariate Power Methods

2000 ◽  
Vol 25 (4) ◽  
pp. 417-436 ◽  
Author(s):  
Todd C. Headrick ◽  
Shlomo S. Sawilowsky
Keyword(s):  
Standard Deviation ◽  
Lower Bound ◽  
Lagrange Multiplier ◽  
Sufficient Conditions ◽  
Efficient Algorithms ◽  
Data Sets ◽  
Transformation Techniques ◽  
Normal Distributions ◽  
Nonnormal Distributions ◽  
Necessary And Sufficient

The power methods are simple and efficient algorithms used to generate either univariate or multivariate nonnormal distributions with specified values of (marginal) mean, standard deviation, skew, and kurtosis. The power methods are bounded as are other transformation techniques. Given an exogenous value of skew, there is an associated lower bound of kurtosis. Previous approximations of the boundary for the power methods are either incorrect or inadequate. Data sets from education and psychology can be found to lie within, near, or outside tile boundary of the power methods. In view of this, we derived necessary and sufficient conditions using the Lagrange multiplier method to determine the boundary of the power methods. The conditions for locating and classifying modes for distributions on the boundary were also derived. Self-contained interactive Fortran programs using a Weighted Simplex Procedure were employed to generate tabled values of minimum kurtosis for a given value of skew and power constants for various (non)normal distributions.

Minimum Sampling Time/Volume for Liquid-Borne Particle Counters and Monitors

1997 ◽  
Vol 40 (6) ◽  
pp. 29-34
Author(s):  
Mindi Xu ◽  
Hwa-Chi Wang
Keyword(s):  
Standard Deviation ◽  
Particle Concentration ◽  
Sample Volume ◽  
Average Concentration ◽  
Sampling Time ◽  
Operating Conditions ◽  
Average Particle ◽  
Particle Counter ◽  
Particle Counts ◽  
The Difference

A particle counter is an instrument that measures particles in all the fluid passing through its sensor, and a particle monitor measures particles only in a portion of the fluid. For liquid with an ultralow particle concentration, particles may not disperse uniformly in the liquid. Therefore, the concentrations may vary significantly from measurement to measurement if the sample volume is not large enough. To achieve the same precision, a minimum sampling time or minimum sample volume for a particle instrument needs to be specified. A Poisson distribution was used to describe the distribution of particle counts. Testing included a series of particle concentration measurements. Minimum sampling time or sample volume at a given average concentration with different error levels was determined for selected commercial particle instruments. At the same flow rate, a particle monitor always requires a longer sampling time than a particle counter to achieve a specific precision for a given concentration. The minimum sampling time also varies among instruments because of the difference in sample volume in which the particles are counted. Experiments with a particle monitor have been conducted to thest the changes in average particle concentration and the standard deviation at different operating conditions.

scholarly journals PENGARUH TERAPI MUROTTAL TERHADAP TINGKAT KONSENTRASI SISWA KELAS VIII. G DI MTSN 2 MUARA ENIM TAHUN 2018

2019 ◽  
Vol 9 (01) ◽  
pp. 44-48
Author(s):  
Shinta Maharani ◽  
Devy Dwi Putri
Keyword(s):  
Standard Deviation ◽  
Experimental Design ◽  
Average Concentration ◽  
A Value ◽  
Significant Difference ◽  
Before And After ◽  
Quasi Experimental ◽  
The Difference ◽  
The One ◽  
Mean Concentration

One of the tasks of the development of children aged 11-15 years is to think in a more abstract and logical way and more idealistic thinking. This ability to think will be disrupted if teenagers have difficulty concentrating during learning. Therefore we need a method that is fun and can make children relax in learning so that they can concentrate their concentration on ongoing learning. One method that can be used is the Murrotal Al-Qur'an therapy. The aim of the study was to determine whether there was any effect of murottal therapy on the concentration of students at Muara Enim 2 MTsN. This study used a quasi-experimental design with the design of the one group pretest posttest. The sample used was all students of class VIII.G at MTsN 2 Muara Enim. The results showed that the average concentration score of class VIII.G students before Murottal therapy was given was 10.84 with a standard deviation of 3.043. While the average concentration score of class VIII.G students after being given murottal therapy was 17.90 with a standard deviation of 1.233, so that the difference in mean concentration scores before and after murottal therapy was 7.06 with a standard deviation of 1.81. Wilcoxon signed ranks test obtained ρ value = 0,000, with a value of α = 0.05 (p <0.05), this shows that there is a significant difference between the concentration of students before and after being given murottal therapy. It is expected that the school can make a policy about the application of murottal therapy in increasing student concentration.

scholarly journals Pengaruh Perbedaan Kadar Oksitosin Melalui Pemijatan Oksitosin Terhadap Jumlah Perdarahan pada Ibu 2 Jam Postpartum

2015 ◽  
Vol 4 (3) ◽  
Author(s):  
Desi Sarli ◽  
Masrul Masrul ◽  
Meilinda Agus
Keyword(s):  
Standard Deviation ◽  
Postpartum Hemorrhage ◽  
Statistical Tests ◽  
Post Partum ◽  
Intervention Group ◽  
Smooth Muscle Contraction ◽  
T Test ◽  
Control Group ◽  
Parasympathetic Nerves ◽  
Significant Difference

Abstrak Upaya penanganan perdarahan postpartum adalah dengan pemberian oksitosin yang mempunyai peranan penting dalam merangsang kontraksi otot polos uterus sehingga perdarahan dapat teratasi.Hormon oksitosin dapat dihasilkan melalui rangsangan pemijatan oksitosin yang akan mempercepat kerja saraf parasimpatis untuk menyampaikan perintah ke hipotalamus untuk menghasilkan oksitosin. Tujuan penelitian ini adalah untuk mengetahui pengaruh perbedaan kadar oksitosin melalui pemijatan oksitosin terhadap jumlah perdarahan pada ibu 2 jam postpartum. Penelitian menggunakan desain eksperimen. Penelitian ini dilaksanakan ± 6 bulan dengan jumlah sampel 64 orang. Pengolahan data dilakukan dengan komputerisasi. Data disajikan dalam bentuk distribusi frekuensi dan selanjutnya dilakukan uji independen t-test, uji korelasi dan regresi untuk mengetahui pengaruh hubungan kedua variabel. Hasil penelitian perbedaan kadar oksitosin pada ibu 2 jam postpartum pada kelompok intervensi mempunyai rata-rata kadar oksitosin 47.16 pg/ml dengan standar deviasi 17.583 pg/ml,sedangkan kadar oksitosin  pada kelompokkontrol 29.86 pg/ml dengan standar deviasi 17.532 pg/ml dengan nilai p<0,05.Rata-rata jumlah perdarahan pada kelompok intervensi 175.00 ml dengan standar deviasi 48.894 ml,sedangkan jumlah perdarahan  pada kelompok kontrol 247.06 ml dengan standar deviasi 72.093 ml dengan nilai p<0,05. Hasil uji korelasi didapatkan hubungan kadaroksitosin terhadap jumlah perdarahan menunjukkan hubungan sedang (r=0,482). Hasil uji statistik didapatkan ada perbedaan kadar oksitosin terhadap jumlah perdarahan (p<0,05). Terdapat perbedaan yang bermakna antara kadar oksitosin ibu 2 jam postpartum pada kelompok intervensi dan kelompok kontrol.Terdapat perbedaan yang bermaknaantara jumlah perdarahan ibu 2 jam postpartum pada kelompok intervensi dan kelompok kontrol. Semakin tinggi kadar oksitosin maka jumlah perdarahan semakin sedikit.Kata kunci: Pemijatan oksitosin, oksitosin, jumlah perdarahan 2 jam postpartumAbstract Efforts to handling postpartum hemorrhage is to give oxytocin,which it is an important role in oxytocin stimulates uterine smooth muscle contraction, so that bleeding can be resolved.The hormone oxytocin can be generated through the stimulation of oxytocin massage that will accelerate parasympathetic nerves to deliver commands to the hipotalamus to produce oxytocin. The objective of this study was to determine effect of different levels of oxytocin trough massage of oxytocin on the amount of bleeding at 2 hours postpartum. This research use experimental designthat was conducted ± 6 months to 64 people. Data processing was done by computerized. The data presented in the form of a frequency distribution and performed an independen t-test and correlation test and regression to determine the effect ofthe relationship between the two variables. There is differences the levels of oxytocin at 2 hours postpartum in the intervention group had higher median levels of oxytocin 47.16pg/ml with a standard deviation of 17.583pg/ml, whereas the levels ofoxytocin at 2 hours post partum control group 29.86 pg/ml with a standard deviation of 17.532 pg/ml with p<0.05. The average of bleeding in the intervention group was 175.00 ml with a standard deviation of 48.894 ml, while the amount of bleeding at 2 hours postpartum control group 247.06 ml with a standard deviation of 72.093 ml with p<0.05. The results obtained correlation levels of oxytocin relation to 2 hours postpartum hemorrhage showed moderate relationship (r =0.482). The results of statistical tests found differences in the levels of oxytocin on the amount of bleeding at 2 hours postpartum (p<0.05). There is differences between the levels of oxytocin 2 hours pos partum in the intervention group and the group control. There are significant difference between the hemorrhage 2 hours post partum in the intervention group and the group of high levels of oxytocin control. Keywords: massage of oxytocin, oxytocin, amount of bleeding at 2 hours postpartum

scholarly journals A new statistical method to analyze Morris Water Maze data using Dirichlet distribution

F1000Research ◽  
2019 ◽  
Vol 8 ◽  
pp. 1601
Author(s):  
Marianne Maugard ◽  
Cyrille Doux ◽  
Gilles Bonvento
Keyword(s):  
Morris Water Maze ◽  
Water Maze ◽  
Dirichlet Distribution ◽  
Statistical Tests ◽  
Individual Variability ◽  
Mean Values ◽  
Normal Distributions ◽  
Memory Impairments ◽  
The Common

The Morris Water Maze (MWM) is a behavioral test widely used in the field of neuroscience to evaluate spatial learning memory of rodents. However, the interpretation of results is often impaired by the common use of statistical tests based on independence and normal distributions that do not reflect basic properties of the test data, such as the constant-sum constraint. In this work, we propose to analyze MWM data with the Dirichlet distribution, which describes constant-sum data with minimal hypotheses, and we introduce a statistical test based on uniformity (equal amount of time spent in each quadrant of the maze) that evaluates memory impairments. We demonstrate that this test better represents MWM data and show its efficiency on simulated as well as in vivo data. Based on Dirichlet distribution, we also propose a new way to plot MWM data, showing mean values and inter-individual variability at the same time, on an easily interpretable chart. Finally, we conclude with a perspective on using Bayesian analysis for MWM data.

scholarly journals Density of bacterial particles cultivable in the air of inside and outside kindergartens in Birjand in 2019

2020 ◽  
pp. 376-384
Keyword(s):  
Significant Relationship ◽  
Statistical Tests ◽  
Geographical Location ◽  
Suspended Particles ◽  
Cross Sectional Study ◽  
Airborne Particles ◽  
Bacterial Density ◽  
Cross Sectional ◽  
Significance Level ◽  
Adverse Health Effects

Background and Aim: Bioaerosols are airborne particles that contain bacteria, viruses and fungi. Human reaction to bioaerosols is very different. The aim of this study was performed to determine the density of bacterial particles cultivable in the air of inside and outside kindergartens in Birjand. Materials and Methods: This descriptive-analytical cross-sectional study was performed. Birjand city was divided into 5 regions based on geographical location and 6 kindergartens were randomly selected. Sampling was done in the morning shift from 6 selected kindergartens.The culture medium used was triptic soy agar for bacteria. Sampling was performed at a flow rate of 28.3 L/Min in 35 minutes at a distance of 0.8 to 1 M above the ground in the center of each class. Statistical analysis was performed using SPSS (Version.16) software and Mann-Whitney and Kruskal-Wallis statistical tests and a significance level (P<0.05) was considered. Results: The results showed that the highest mean bacterial microbial load in February was (3.83±8.04) CFU/m3 and suspended particles in March (196.13±382.54) CFU/m3. There was no significant relationship between bacterial density with suspended particles and temperature (P>0.05). There was a significant relationship between bacterial density and total suspended particles (P<0.05). There was a significant relationship between the amount of suspended particles (PM1, PM2.5, PM10) with the environment inside and outside the kindergarten (P<0.05). Conclusion: From the findings of this study, the concentration of bacterial contamination in terms of quantity and type of identified species and the amount of airborne particles can be identified to prevent adverse health effects.

scholarly journals Assessing the Mental Workload of staff in a Bank in Hamadan by NASA-TLX Method

2021 ◽  
Author(s):  
Zohreh BAKHSHI ◽  
Majid MOTAMEDZADE ◽  
Maryam FARHADIAN
Keyword(s):  
Standard Deviation ◽  
Work Experience ◽  
Mental Workload ◽  
Statistical Tests ◽  
Pearson Correlation ◽  
Cross Sectional ◽  
Mental Demand ◽  
The Mean ◽  
Bank Employees ◽  
Nasa Tlx

Introduction: Mental workload is one of the effective factors on the performance and efficiency of people working in an organization that put their health at risk. The aim of this study was to determine the mental workload of staffa working in a bank in Hamadan City of Iran  by NASA-TLX method. Methods: In this cross-sectional study, 110 bank employees were surveyed. The data were collected using demographic and NASA-TLX questionnaires. Finally, collected data were analyzed using SPSS version 21 by running descriptive statistics and statistical tests. Results: According to the participants, the mean and standard deviation of effort and mental demand, as the most important dimensions were 81.04 ± 14.51 and 79.50 ± 18.05, respectively. The performance dimension was selected as the least important dimension with the mean and standard deviation of 64.37 ± 10.17. The results of statistical analysis showed no significant relationship between the participants' total score of mental workload and their demographic information such as age, gender, educational level, marital status, experience, and work overtime(P>0.05). The Pearson correlation coefficient showed that age (P<0.05) and work experience (P<0.01) had a significant and inverse relationship with temporal demand dimension . Conclusion: Based on the findings, the mean of perceived mental workload of bank employees was high. Therefore, effective programs should be conducted to mitigate and reduce the mental workload and to promote mental health of bank employees.

scholarly journals Platelet Determination by Turbidimetry

Blood ◽  
1954 ◽  
Vol 9 (9) ◽  
pp. 920-926 ◽  
Author(s):  
W. O. CRUZ
Keyword(s):  
Standard Deviation ◽  
Light Absorption ◽  
Statistical Tests ◽  
Platelet Volume ◽  
Platelet Suspension ◽  
Surgical Interventions ◽  
Special Apparatus ◽  
Photoelectric Apparatus ◽  
Male Patients ◽  
Blood Elements

Abstract A method to determine the amount of circulating platelets without the aid of any special apparatus is described. The method consists in separating the platelets from the other blood elements by fractional centrifugation and in measuring the light absorption of the platelet suspension in a photoelectric apparatus. Light absorption is standardized against the platelet volume found by the Van Allen thrombocytocrit, and results presented as platelet volume in 100 ml. of bood. The error of the method was found to be 6 per cent. To test the consistency of the method, normal dogs and patients of both sexes with different pathologic conditions were studied, the results agreeing with the data found in the literature. In dogs of both sexes, twenty males showed 0.50 ml. per 100 ml. blood with a standard deviation of ±0.15, and ten females 0.53 ml./100 ml. ±0.17; fiftytwo male patients showed 0.45 ml. per 100 ml. of blood with a standard deviation of ±0.20, and thirty-one females 0.44 ml./100 ml. ±0.23. Still further to test the reliability of the method, a confirmation was undertaken of the fact of platelet increase in the postoperative period in major surgical interventions. Twenty-seven patients with 0.38 ml./100 ml. (±0.16 as standard deviation) platelets showed soon after the operation 0.44 ml./100 ml. ±0.19 a difference not significant according to statistical tests; eleven days after the operation, average platelets were 0.60 ± 0.21 ml./100 ml. a highly significant increase.

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