The Estimation of the Efficiency of Sampling, with Special Reference to Sampling for Yield in Cereal Experiments

1935 ◽  
Vol 25 (4) ◽  
pp. 545-577 ◽  
Author(s):  
F. Yates ◽  
I. Zacopanay
Keyword(s):  
Standard Deviation ◽  
Special Reference ◽  
Analysis Of Variance ◽  
Sampling Methods ◽  
Cereal Crops ◽  
Loss Of Information ◽  
Preliminary Discussion ◽  
Experimental Errors ◽  
Series Of Experiments ◽  
The Mean

The estimation of the experimental yields of cereal crops by sampling methods is considered in the light of results of eighteen experiments which were harvested by these methods at Rothamsted and its associated centres. The harvesting results of the Crop-Weather series of experiments are also included.A preliminary discussion of the interpretation of the analysis of variance as applied to sampling results is given, and an expression is found for the loss of information arising out of sampling. The results of the discussion are applicable to all types of sampling carried out on replicated experiments.The sampling and experimental errors of all the experiments have been calculated. The variation between sampling units in the same subplot (usually between l/100th and l/200th acre) was found to be such as would arise if each metre length of row had a standard deviation (about the plot mean) of the order of 25–30 per cent. of the mean yield.

Robust Statistics: A Survey and Some Prescriptions

1976 ◽  
Vol 1 (4) ◽  
pp. 285-312 ◽  
Author(s):  
Howard Wainer
Keyword(s):  
Factor Analysis ◽  
Multivariate Analysis ◽  
Standard Deviation ◽  
Principal Components Analysis ◽  
Analysis Of Variance ◽  
Principal Components ◽  
Robust Statistics ◽  
Robust Methods ◽  
The Mean ◽  
Components Analysis

It is noted that the usual estimators that are optimal under a Gaussian assumption are very vulnerable to the effects of outliers. A survey of robust alternatives to the mean, standard deviation, product moment correlation, t-test, and analysis of variance is offered. Robust methods of factor analysis, principal components analysis and multivariate analysis of variance are also surveyed, as are schemes for outlier detection.

scholarly journals The difference in the measurement of freeway space in an upright sitting position with and without electromyograph

2015 ◽  
Vol 27 (1) ◽  
Author(s):  
Stevani Monika Halim ◽  
Taufik Sumarsongko ◽  
Aprilia Adenan
Keyword(s):  
Standard Deviation ◽  
Comparative Study ◽  
Sampling Methods ◽  
Vertical Dimension ◽  
Sitting Position ◽  
Test Statistics ◽  
Accuracy Of Measurements ◽  
The Mean ◽  
The Difference ◽  
Seating Position

Introduction: Measurement of vertical dimension is very important because improper measurement of vertical dimension may create stomatognatic problem. Electromyography is a tool for recording electrical signals generated from the mechanism of muscle contraction.This study aims to determine the accuracy of measurements of FWS with and without electromyograph.  Methods: This research was a descriptive comparative study using purposive sampling methods. Measurements of FWS in an upright sitting position with and without electromyograph were done on 10 students of class 2008 from Faculty of Dentistry, UNPAD who met the criteria. Data were analyzed by t test statistics, showed that there were significant differences in the measurements with and without electromyography in upright sitting position. Results: The mean of FWS measured with electromyography was 2.38 mm with standard deviation of 0.44 mm, whereas the mean of FWS measured without electromyography was 1.69 mm with a standard deviation of 0.46 mm. Average FWS in men measured with electromyography was 2.51 mm with a standard deviation of 0.15 mm, whereas the mean without electromyography was 1.68 mm with a standard deviation of 0.43 mm. Average FWS in women measured with electromyography was 2.35 mm with a standard deviation of 0.49 mm, whereas the mean without electromyography was 1.69 mm with a standard deviation of 0.50 mm. Conclusion: The measurements of FWS with electromyograph in an upright seating position was greater than without electromyography.

scholarly journals MKG Angle: A True Marker for Maxillomandibular Discrepancy

2020 ◽  
Vol 54 (3) ◽  
pp. 220-225
Author(s):  
Achint Chachada ◽  
Payal Ostwal ◽  
Megha Jain ◽  
Piyush Khandelwal ◽  
Jamoy James ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Analysis Of Variance ◽  
Roc Curves ◽  
Class Iii ◽  
Lateral Cephalograms ◽  
Skeletal Pattern ◽  
The Mean ◽  
The One ◽  
Point G ◽  
Maxilla And Mandible

Aim: To evolve a new cephalometric estimation called the MKG angle using three skeletal landmarks—point key ridge (KR), point M, and point G to evaluate the sagittal relationship between the maxilla and mandible. Materials and methods: A total of 60 pretreatment lateral cephalograms were selected and segregated into classes I, II, and III groups on the basis of ANB angle, Wits appraisal, and W angle. The MKG angle was constructed between the lines drawn from point M to point KR and point KR to point G. The MKG angle was measured to calculate the mean and the standard deviation. Results: After using the one-way analysis of variance and the Newman–Keuls test and running ROC curves, the results showed that an MKG angle in the range 51º–59º can be considered to have a class I skeletal pattern. The MKG angle more than 59º indicates a class II skeletal pattern and less than 51º indicates class III skeletal pattern. Conclusion: The MKG angle can be used as a dependable marker to assess sagittal jaw discrepancy.

scholarly journals Academic Procrastination among Gifted and Ordinary Students and its Relationship with Some Variables

2017 ◽  
Vol 9 (3) ◽  
pp. 32
Author(s):  
Ziad Khamis El-tah ◽  
Wael Mohammad Alsharman
Keyword(s):  
Standard Deviation ◽  
Analysis Of Variance ◽  
Gifted Students ◽  
T Test ◽  
Academic Procrastination ◽  
Validity And Reliability ◽  
Negative Effects ◽  
Counseling Programs ◽  
The Mean ◽  
Standard Deviations

This study aims at identifying the academic procrastination among a sample of gifted and ordinary students and its relationship with some variables. It consists of 151 students: (74 are gifted students from King Abdullah II School of Excellence, whereas 77 are ordinary students). The researchers designed a questionnaire of academic procrastination for this study. Then its validity and reliability were verified. To answer the study questions, means, standard deviations, percentages, one way analysis of variance (2 * 2) and T-test were used. The results show that the academic procrastination of gifted students is low (mean score 44.36, standard deviation 10.051). The percentage of gifted students with academic procrastination is 37.8. However, the academic procrastination of ordinary students is high with a mean of 50.94 and a standard deviation 10.20, and the mean of ordinary students with academic procrastination is 58.4. Moreover, the results show that there are no statistical significant differences at α ≤ 0.05 in academic procrastination among gifted students due to gender, grade and the interaction between them. However, there are significant differences at α ≤ 0.05 in academic procrastination among ordinary students due to gender. In addition, there are no statistical significant differences at α ≤ 0.05 in academic procrastination due to grade and interaction between gender and grade. Thus, there are statistical significant differences at α ≤ 0.05 between gifted and ordinary in academic procrastination in favor of the ordinary students. This study recommends that counseling programs should be considered to reduce the negative effects of academic procrastination among gifted and ordinary students.

At Least One Standard Deviation Above the Mean

1969 ◽  
Vol 14 (9) ◽  
pp. 470-471
Author(s):  
M. DAVID MERRILL
Keyword(s):  
Standard Deviation ◽  
The Mean

The Estimation of Blood Platelet Survival

1972 ◽  
Vol 28 (03) ◽  
pp. 447-456 ◽  
Author(s):  
E. A Murphy ◽  
M. E Francis ◽  
J. F Mustard
Keyword(s):  
Standard Deviation ◽  
Least Squares ◽  
Experimental Error ◽  
Blood Platelet ◽  
Least Squares Estimation ◽  
Systematic Relationship ◽  
Platelet Survival ◽  
The Mean ◽  
Normally Distributed

SummaryThe characteristics of experimental error in measurement of platelet radioactivity have been explored by blind replicate determinations on specimens taken on several days on each of three Walker hounds.Analysis suggests that it is not unreasonable to suppose that error for each sample is normally distributed ; and while there is evidence that the variance is heterogeneous, no systematic relationship has been discovered between the mean and the standard deviation of the determinations on individual samples. Thus, since it would be impracticable for investigators to do replicate determinations as a routine, no improvement over simple unweighted least squares estimation on untransformed data suggests itself.

PENGARUH PENDIDIKAN KESEHATAN REPRODUKSI PADA PEER GROUP (TEMAN SEBAYA) TERHADAP PENGETAHUAN DAN PERSEPSI REMAJA TENTANG PENDEWASAAN USIA PERKAWINAN DI SMA NEGERI 1 KECAMATAN NAMORAMBE KAB. DELI SERDANG 2018

2020 ◽  
Vol 1 (2) ◽  
pp. 56-66
Author(s):  
Irma Linda
Keyword(s):  
Standard Deviation ◽  
Health Education ◽  
Reproductive Health ◽  
Peer Group ◽  
Peer Groups ◽  
A Value ◽  
Significant Difference ◽  
Reproductive Health Education ◽  
The Mean ◽  
Adolescent Perceptions

Background: Early marriages are at high risk of marital failure, poor family quality, young pregnancies at risk of maternal death, and the risk of being mentally ill to foster marriage and be responsible parents. Objective: To determine the effect of reproductive health education on peer groups (peers) on the knowledge and perceptions of adolescents about marriage age maturity. Method: This research uses the Quasi experimental method with One group pre and post test design, conducted from May to September 2018. The statistical analysis used in this study is a paired T test with a confidence level of 95% (α = 0, 05). Results: There is an average difference in the mean value of adolescent knowledge between the first and second measurements is 0.50 with a standard deviation of 1.922. The mean difference in mean scores of adolescent perceptions between the first and second measurements was 4.42 with a standard deviation of 9.611. Conclusion: There is a significant difference between adolescent knowledge on the pretest and posttest measurements with a value of P = 0.002, and there is a significant difference between adolescent perceptions on the pretest and posttest measurements with a value of p = 0.001. Increasing the number of facilities and facilities related to reproductive health education by peer groups (peers) in adolescents is carried out on an ongoing basis at school, in collaboration with local health workers as prevention of risky pregnancy.

Regularity and latency of units in ventral cochlear nucleus: implications for unit classification and generation of response properties

1988 ◽  
Vol 60 (1) ◽  
pp. 1-29 ◽  
Author(s):  
E. D. Young ◽  
J. M. Robert ◽  
W. P. Shofner
Keyword(s):  
Standard Deviation ◽  
Cochlear Nucleus ◽  
Interspike Interval ◽  
Rate Adaptation ◽  
Stellate Cells ◽  
Instantaneous Rate ◽  
Ventral Cochlear Nucleus ◽  
Bushy Cell ◽  
Low Pass ◽  
The Mean

1. The responses of neurons in the ventral cochlear nucleus (VCN) of decerebrate cats are described with regard to their regularity of discharge and latency. Regularity is measured by estimating the mean and standard deviation of interspike intervals as a function of time during responses to short tone bursts (25 ms). This method extends the usual interspike-interval analysis based on interval histograms by allowing the study of temporal changes in regularity during transient responses. The coefficient of variation (CV), equal to the ratio of standard deviation to mean interspike interval, is used as a measure of irregularity. Latency is measured as the mean and standard deviation of the latency of the first spike in response to short tone bursts, with 1.6-ms rise times. 2. The regularity and latency properties of the usual PST histogram response types are shown. Five major PST response type classes are used: chopper, primary-like, onset, onset-C, and unusual. The presence of a prepotential in a unit's action potentials is also noted; a prepotential implies that the unit is recorded from a bushy cell. 3. Units with chopper PST histograms give the most regular discharge. Three varieties of choppers are found. Chop-S units (regular choppers) have CVs less than 0.35 that are approximately constant during the response; chop-S units show no adaptation of instantaneous rate, as measured by the inverse of the mean interspike interval. Chop-T units have CVs greater than 0.35, show an increase in irregularity during the response and show substantial rate adaptation. Chop-U units have CVs greater than 0.35, show a decrease in irregularity during the response, and show a variety of rate adaptation behaviors, including negative adaptation (an increase in rate during a short-tone response). Irregular choppers (chop-T and chop-U units) rarely have CVs greater than 0.5. Choppers have the longest latencies of VCN units; all three groups have mean latencies at least 1 ms longer than the shortest auditory nerve (AN) fiber mean latencies. 4. Chopper units are recorded from stellate cells in VCN (35, 42). Our results for chopper units suggest a model for stellate cells in which a regularly firing action potential generator is driven by the summation of the AN inputs to the cell, where the summation is low-pass filtered by the membrane capacitance of the cell.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Blood Oxygenation Level Dependent Magnetic Resonance Imaging (MRI), Dynamic Contrast Enhanced MRI and Diffusion Weighted MRI for Benign and Malignant Breast Cancer Discrimination: A Preliminary Experience

Cancers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 2421
Author(s):  
Roberta Fusco ◽  
Vincenza Granata ◽  
Mauro Mattace Raso ◽  
Paolo Vallone ◽  
Alessandro Pasquale De Rosa ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Univariate Analysis ◽  
Mean Value ◽  
Blood Oxygenation ◽  
Breast Lesions ◽  
Dce Mri ◽  
Malignant Lesions ◽  
The Mean ◽  
And Diffusion ◽  
Skewness And Kurtosis

Purpose. To combine blood oxygenation level dependent magnetic resonance imaging (BOLD-MRI), dynamic contrast enhanced MRI (DCE-MRI), and diffusion weighted MRI (DW-MRI) in differentiation of benign and malignant breast lesions. Methods. Thirty-seven breast lesions (11 benign and 21 malignant lesions) pathologically proven were included in this retrospective preliminary study. Pharmaco-kinetic parameters including Ktrans, kep, ve, and vp were extracted by DCE-MRI; BOLD parameters were estimated by basal signal S0 and the relaxation rate R2*; and diffusion and perfusion parameters were derived by DW-MRI (pseudo-diffusion coefficient (Dp), perfusion fraction (fp), and tissue diffusivity (Dt)). The correlation coefficient, Wilcoxon-Mann-Whitney U-test, and receiver operating characteristic (ROC) analysis were calculated and area under the ROC curve (AUC) was obtained. Moreover, pattern recognition approaches (linear discrimination analysis and decision tree) with balancing technique and leave one out cross validation approach were considered. Results. R2* and D had a significant negative correlation (−0.57). The mean value, standard deviation, Skewness and Kurtosis values of R2* did not show a statistical significance between benign and malignant lesions (p > 0.05) confirmed by the ‘poor’ diagnostic value of ROC analysis. For DW-MRI derived parameters, the univariate analysis, standard deviation of D, Skewness and Kurtosis values of D* had a significant result to discriminate benign and malignant lesions and the best result at the univariate analysis in the discrimination of benign and malignant lesions was obtained by the Skewness of D* with an AUC of 82.9% (p-value = 0.02). Significant results for the mean value of Ktrans, mean value, standard deviation value and Skewness of kep, mean value, Skewness and Kurtosis of ve were obtained and the best AUC among DCE-MRI extracted parameters was reached by the mean value of kep and was equal to 80.0%. The best diagnostic performance in the discrimination of benign and malignant lesions was obtained at the multivariate analysis considering the DCE-MRI parameters alone with an AUC = 0.91 when the balancing technique was considered. Conclusions. Our results suggest that the combined use of DCE-MRI, DW-MRI and/or BOLD-MRI does not provide a dramatic improvement compared to the use of DCE-MRI features alone, in the classification of breast lesions. However, an interesting result was the negative correlation between R2* and D.

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