Is standard deviation always the right choice?

1986 ◽  
Vol 143 (9) ◽  
pp. 1198-1199
Keyword(s):  
2018 ◽  
Author(s):  
Natarajan Sriram ◽  
Brian A. Nosek ◽  
Anthony G. Greenwald

Individual differences in general speed lead to a positive correlation between the mean and standard deviation of mean latency. This “coarse” scaling effect causes the mean latency difference (MLD) to be spuriously correlated with general speed. Within individuals, the correlation between the mean and standard deviation of trial latencies leads contrasted distributions to increase their overlap as an MLD of fixed width is translated to the right. To address this “fine” scaling effect, contrasts based on within subject latency transformations including the logarithm, standardization, and ranking were evaluated and turned out to be distinctly superior to the MLD. Notably, the mean gaussian rank latency difference was internally consistent, eliminated fine scaling, meliorated coarse scaling, reduced correlations with general speed, increased statistical power to detect within subject and between group effects, and has the potential to increase the validity of inferences drawn from response latency data.


2018 ◽  
Vol 16 (1) ◽  
pp. 51-64
Author(s):  
Miftachul Ulum

Abstract: In every decision made by the business, it is always confronted with an uncertainty that we know as risks. Stakeholders are those who influence or will be influenced by the decision. Statistically risk can be formulated as a deviation. The magnitude of risk can be measured by variance (?2) or standard deviation (?). Through prudential principles, the types and forms of risk can be avoided or minimized. The carelessness is a factor of human error which is a factor beyond human reason. Humans are only able to put the basic concept of prudence in making decisions but all the terms of haqiqi will be the right of the Almighty.  Abstraksi : Setiap pengambilan keputusan yang dilakukan oleh pelaku bisnis selalu dihadapkan  pada suatu ketidakpastian yang kita kenal dengan risiko. Stakeholder sebagai pemangku kepentingan merupakan pihak yang mempengaruhi atau yang akan dipengaruhi  keputusan tersebut. Secara statistik risiko dapat dirumuskan sebagai penyimpangan, besarnya risiko dapat diukur dengan variance (?2) atau standar deviasi. Melalui prinsip kehati-hatian jenis dan bentuk risiko dapat dihindari atau bahkan dapat diminimalkan. Kelalaian adalah   merupakan suatu  faktor yang diluar nalar manusia. Manusia hanya meletakkan konsep dasar kehati-hatian dalam mengambil keputusan namun ketentuan secara haqiqi menjadi hak Yang Maha Kuasa.


2021 ◽  
Vol 19 (6) ◽  
pp. 98-106
Author(s):  
Monawar Muhsin Jabr ◽  
Hussain S. Hasan ◽  
Hind Ahmed Mahdi

Background: Chronic kidney disease (CKD) is a public health problem over all the world. CKD may also be defined by the presence of kidney damage or a reduced glomerular filtration rate (GFR), which is the best overall indicator or index of kidney function. CKD patients are usually treated using kidney dialysis (hemodialysis) that uses a blood filtration mechanism (HD). Several metabolic parameters, such as blood urea, sodium, potassium, and glucose levels, can alter during HD. Osmotic alterations in blood, aqueous and vitreous humor, and other extracellular fluids arise from these fluctuations. That also can affect visual acuity, intraocular pressure (IOP), and retinal thickness. Aim of the Study: To evaluate some of the ocular findings undergoing HD to keep prevent the loss of patient vision such as visual acuity (VA), intraocular pressure (IOP), central corneal thickness (CCT), central Foveal Thickness (CFT), retinal nerve fiber layer (RNFL). Patient& Methods: This is a cohort (prospective) design study. This study including Seventy nine patients divided into two groups the first group from one week to six month (9 femal & 18 males) another group over than six month (36 female & 16 male) the average age between (12 to 70 years). This research performed in the three places department of the eye in Al-Hussein hospital in Samawah city, Al-Haboby hospital, Al-Hussein hospital in Dhi Qar city finally in Al-Shaheed Gazy hospital and Baghdad teaching hospital in Baghdad. Examining Visual Acuity by Snellen chart & auto refractometer, IOP& CCT by (CT.1 Computerized Tonometer TOPCON), RNLF and Central Foveal Thickness by OCT (Carl ZEISS, TOPCON). The inclusion criteria were as follows: all the patients undergoing dialysis from one week to over six months. Exclusion criteria were as follows: the patients have diabetic, any patients have a hereditary disease or glaucoma history or laser therapy, or intraocular injection in the eye before dialysis, the patients have a problem in the eye before dialysis such as cataracts or opacity leads to does surgery, the patients who have a refractive error or wear glass had been also excluded. Result: Includes the results of seventy-nine patients (45 females and 34 males) with chronic kidney disease examined ocular findings before a session of dialysis divided into two groups based on their duration of dialysis. Group one with twenty-seven patients (9 female & 18 male) under dialysis from one week to six months with mean & standard deviation (3.2037, ± 1.89259), group tow with fifty tow patients (36 female & 16 male) under dialysis from the duration over than six months with mean & standard deviation (44.2308, ± 26.24367) respectively. Patients aged (12 to 70 years) had mean age & ± standard deviation (35.1481, ± 12.88918), (44.4038, ± 15.42249) for two groups respectively. Patients in two groups had IOP (Right eye), its mean & standard deviation (15, ± 2.34), (15.69, ± 2.56) for group one & group tow respectively. Also, patients had CCT (Right eye) with mean & standard deviation (5.3467E2, ± 39.00296), (5.2312E2, ± 30.44162) for group one & group tow respectively. Patients had CCT (Left) with mean & standard deviation (5.2878E2, ± 37.55748), (5.2179E2, ± 29.58957) for group one & group tow respectively. Patients in two groups had average thickness RNFL (Right eye) with mean & standard deviation (1.0604E2, ± 25.17551), (95.6154, ± 21.27150) for group one & group tow respectively. Also, patients had average thickness RNFL (left eye) with mean & standard deviation (1.0930E2, ±23.80177), (98.7500, ± 23.77334) for group one & group tow respectively. Conclusions: This study found CCT effective with dialysis tend to be thin (53 patient,18 patient in group one &35 in group two) and that will be had a threefold higher risk of developing glaucoma when compared with thick average because of the IOP value affected by it. Refractive error effective with dialysis & become was more prominent that can be shown in the group two have (40 patient from 52) while (15 patient from27) in the group one although a lot of them corrected to the BCVA. In conclusion high value of the C/D ratio formed about (45.57%, 53.16%) to the right &left eye respectively this value will be form important sign of risk factor to progressive of glaucomatous need to be alert in the future. Also our research reveals CFT effective undergoing dialysis the thick value was (56 in the right eye, 55 in the left eye) high compared with the thin (9 in the right&9 in the left eye) & normal (14 in the right eye, 15 in the left eye). All the two groups of patients will be effected by the duration of dialysis with a time.


2017 ◽  
Vol 13 (1) ◽  
pp. 7-12 ◽  
Author(s):  
R. Guire ◽  
H. Mathie ◽  
M. Fisher ◽  
D. Fisher

The horse-rider system is of great interest in understanding the mechanics involved in optimising locomotor function and performance in the ridden horse. Adult riders (n=30) attending a rider conference volunteered to take part in the study. Riders were asked to mimic riding position by positioning themselves symmetrically on their seat bones (ischial tuberosities) sitting on a (Pliance) pressure mat which was placed on a static platform. Riders were also asked to mimic even rein contact using reins with gauges which were attached to a solid wall. When satisfied that they were sitting symmetrically and had an even rein contact, pressure and rein measurements were captured for 5 s and repeated three times. A paired T Test was carried out to determine differences between left and right ischial tuberosities and rein pressures. Using a static model, this study found that the riders had significantly more pressure beneath the left ischial tuberosity (mean ± standard deviation, 3.22±1.43 N/cm2) compared to the right (2.65±1.49 N/cm2) (P=0.04) and no significant differences were observed between left (6.37±2.42 N) and right rein pressure (6.38±2.66 N) (P=0.95). Whilst sitting on a static platform, differences in ischial tuberosity pressure in adult riders were observed despite these riders’ perception that their seat was symmetrically weighted. These differences observed need to be investigated further, dynamically, to determine if there is a similar trend in the ridden situation.


Author(s):  
Ruohan Zhao ◽  
Feng Xiong ◽  
Xiaoqi Deng ◽  
Shuzhen Wang ◽  
Chunxia Liu ◽  
...  

Aim To evaluate ventricular synchronization and function in patients with right bundle-branch block after left bundle-branch-area pacing (LBBAP) by echocardiography. Methods Forty patients who successfully received LBBAP were selected and divided into the right bundle-branch block group (RBBB group) and the non-RBBB group by pre-operation ECG. Echocardiography and follow-up were performed 1 month after operation. Interventricular synchronization was evaluated by tissue Doppler (TDI), tissue mitral annular displacement (TMAD), and interventricular mechanical delay (IVMD). The ventricular longitudinal strain and the standard deviation of peak time of longitudinal strain were analyzed by two-dimensional speckle tracking imaging (2D-STI) to evaluate intraventricular synchronization and ventricular function. Results (1) The deviation of systolic time to the peak of the tricuspid and mitral valves, namely ΔPTTV-MV measured by TMAD and ΔTsTV-MV measured by TDI, were statistically different between the two groups (P < 0.05). (2) Compared with the non-RBBB group, there were no statistically significant differences in longitudinal strain (LS), peak strain time, standard deviation of peak strain time (SDt), and global longitudinal strain (GLS) in the right and left ventricle in the RBBB group (P > 0.05). Conclusion Echocardiography technology including 2D-STI, TDI, and TMAD can effectively analyze interventricular synchronization, intraventricular synchronization, and ventricular function. Although the movement of the right ventricular myocardium in the RBBB group treatment was slightly later than that of the left ventricular myocardium after LBBAP, LBBAP is still an effective pacing therapy for RBBB patients with pacing indication.


2004 ◽  
Vol 36 (3) ◽  
pp. 1338
Author(s):  
Γ. Αιμ. Σκιάνης ◽  
Δ. Βαϊόπουλος ◽  
Κ. Νικολακόπουλος

In the present paper the statistical behaviour of the Transformed Vegetation Index TVI is studied. TVI is defined by: (equation No1) - or, alternatively, by: (equation No2) u is the numerical value of the vegetation index, χ and y are the brightness values of the near infrared and red zones, respectively. Relation (1) defines the vegetation index TVI. Relation (2) defines the vegetation index TVI'. Using appropriate distributions to describe the histograms of χ and y channels, and taking into account certain theorems from probability theory, the expressions for the distributions of TVI and TVI' values are deduced. According to these expressions, the standard deviation of TVI image is larger than that of TVI', as well as NDVI (Normalized Difference Vegetation Index). The prevailing value of the TVI' histogram is located at the right part of the tonality range. Therefore, according to the mathematical analysis, the TVI image has a better contrast than that of the NDVI and TVI' images. The TVI' has a diffuse luminance. The theoretical predictions were tested with a Landsat 7 ETM image of Zakynthos Island (western Greece) and they were found to be in accordance with the satellite data. It was also observed that lineaments with a dark tonality are expressed more clearly in the TVI image than in the TVI' image. The general conclusion is that the TVI vegetation index is preferable from TVI', since the former produces images with a larger standard deviation and a better contrast than the latter. The results and conclusions of this paper may be useful in geological and environmental research , for mapping regions with a different vegetation cover.


1996 ◽  
Vol 1 (4) ◽  
pp. E1
Author(s):  
Atsushi Koike ◽  
Hiroyuki Shimizu ◽  
Ichiro Suzuki ◽  
Buichi Ishijima ◽  
Morihiro Sugishita

It has been widely accepted that the right temporal lobe plays a major role in the processing of music. One of the main lines of evidence was derived from Milner's study, published in 1962, which reported that right temporal lobectomy led to a decline in patient scores on four of the six subtests (Tonal Memory, Timbre, Loudness, and Time subtests) of the Seashore Measures of Musical Talents. That finding had led some surgeons and patients to hesitate in choosing right temporal lobectomy as a treatment for intractable epilepsy. The authors examined performance on the Seashore Measures before and after operations in 20 patients with right temporal lobectomy and nine patients with left temporal lobectomy. No disturbances in the Seashore Measures were detected after temporal lobectomy on either side. The extent of these temporal lobectomies was smaller than that of the temporal lobectomies in Milner's study, as measured along the sylvian fissure (1.5–4 cm; mean 2.7 cm, standard deviation (SD) 0.92 cm) and the base of the temporal lobe (3.5–5.5 cm; mean 4.7 cm, SD 0.63 cm). These findings indicate that the region resected on right temporal lobectomy in the present study is not essential for basic musical processing.


Fishes ◽  
2021 ◽  
Vol 6 (4) ◽  
pp. 60
Author(s):  
Sergio G. Castillo-Vargasmachuca ◽  
Eugenio Alberto Aragón-Noriega ◽  
Guillermo Rodríguez-Domínguez ◽  
Leonardo Martínez-Cárdenas ◽  
Eulalio Arámbul-Muñoz ◽  
...  

In the present study, size-at-age data (length and weight) of marine cage-reared spotted rose snapper Lutjanus guttatus were analyzed under four different variance assumptions (observed, constant, depensatory, and compensatory variances) to analyze the robustness of selecting the right standard deviation structure to parametrize the von Bertalanffy, Logistic, and Gompertz models. The selection of the best model and variance criteria was obtained based on the Bayesian information criterion (BIC). According to the BIC results, the observed variance in the present study was the best way to parametrize the three abovementioned growth models, and the Gompertz model best represented the length and weight growth curves. Based on these results, using the observed error structure to calculate the growth parameters in multi-model inference analyses is recommended.


2018 ◽  
Vol 16 (4) ◽  
pp. 285-298 ◽  
Author(s):  
Mithun S. Ullal ◽  
Iqbal Thonse Hawaldar

The paper is based on information which is a combination of store advertisement and consumers’ path inside the store along with product information. With this information, the authors find how advertisement affects the behavior of consumers when making the decision. The findings suggest that advertisement has a small impact on customers inside the stores. Null effect is determined, and one standard deviation in advertising has an impact on store traffic by 1.2%. But the impact at a lower end of the model is observed. One standard deviation in advertisement has impacted the store sales by 8.4%. Based on further data mining, the research has found that there is no significant improvement in the number of customers, but the increase in sales is because of the higher quantity of purchases by the existing consumers. However, the effect of advertisement on products placed in the same or nearby shelf is not found, the impact on product varieties in the same segment is also not found. Based on these research findings, the authors find the right approach towards advertisement.The research is limited to consumers of retail industry in a Tier 3 Indian city of a developing geographic segment only.


2020 ◽  
Vol 31 (4) ◽  
pp. 395-445
Author(s):  
Andrea Bonoldi ◽  
Chiara Dalle Nogare ◽  
Martin Mosler ◽  
Niklas Potrafke

Abstract We examine the relationship between inheritance rules and voter turnout. Inheritance rules are measured by entailed farms in South Tyrol: land properties whose inheritance is regulated by a law similar to the right of primogeniture. Using data for municipalities between 1998 and 2010, we show that voter turnout is high in municipalities with many entailed farms relative to population. The effect is based on local elections. If the number of entailed farms per 100 inhabitants increases by one standard deviation, voting turnout in municipal and provincial elections increases by around 1.27 and 1.43 percentage points (around 25 and 35% of a standard deviation). Our results suggest that entailed farm owners themselves are more likely to vote, and that entailed farms owners encourage other citizens of their municipality to participate in local elections.


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