A New Way to View the Magnitude of the Difference between the Arithmetic Mean and the Geometric Mean and the Difference between the Slopes When a Continuous Dependent Variable Is Expressed in Raw Form Versus Logged Form

2017 ◽  
Vol 47 (1) ◽  
pp. 165-181
Author(s):  
Leo A. Goodman
Keyword(s):  
Present Note ◽  
Geometric Mean ◽  
Arithmetic Mean ◽  
Form Versus ◽  
Geometric Means ◽  
Dependent Variables ◽  
The Difference ◽  
Group 2 ◽  
Multiplicative Models ◽  
Group 1

In Trond Petersen’s “Multiplicative Models for Continuous Dependent Variables: Estimation on Unlogged versus Logged Form” (this volume, pp. 113–164), the following phenomenon is noted: With the arithmetic and geometric means of a nonnegative quantitative variable measured for two groups (say, groups 1 and 2), it is possible for the arithmetic mean [Formula: see text] for group 1 to be larger than the arithmetic mean [Formula: see text] for group 2 and the geometric mean [Formula: see text] for group 1 to be smaller than the geometric mean [Formula: see text] for group 2. In the present note, some new formulas are introduced that will help to make clear when this phenomenon will occur and when it will not occur. The phenomenon considered here is of interest in situations where, for example, as noted in Petersen’s paper, results obtained using the raw form for a continuous dependent variable are compared with the corresponding results obtained using the logged form for the dependent variable. In addition, the formulas that are introduced in the present note also provide a new way to view the magnitude of the difference between the arithmetic mean and the geometric mean.

The Risk Premium on Ordinary Shares

1995 ◽  
Vol 1 (2) ◽  
pp. 251-330 ◽  
Author(s):  
A.D. Wilkie
Keyword(s):  
Risk Premium ◽  
Geometric Mean ◽  
Arithmetic Mean ◽  
Short Term ◽  
Arithmetic Means ◽  
Price Inflation ◽  
Geometric Means ◽  
True Model ◽  
The Difference

ABSTRACTThe risk premium on ordinary shares is investigated, by studying the total returns on ordinary shares, and on both long-term and short-term fixed-interest investments over the period 1919 to 1994, and by analysing the various components of that return. The total returns on ordinary shares exceeded those on fixed-interest investments by over 5% p.a. on a geometric mean basis and by over 7% p.a. on an arithmetic mean basis, but it is argued that these figures are misleading, because most of the difference can be accounted for by the fact that price inflation turned out to be about 4.5% p.a. over the period, whereas investors had been expecting zero inflation.Quotations from contemporary authors are brought forward to demonstrate what contemporary attitudes were. Simulations are used along with the Wilkie stochastic asset model to show what the results would be if investors make various assumptions about the future, but the true model turns out to be different from what they expected. The differences between geometric means of the data and arithmetic means are shown to correspond to differences between using medians or means of the distribution of future returns, and it is suggested that, for discounting purposes, medians are the better measure.

Administration of Single-Dose Antibiotic Does Not Decrease Oronasal Fistula Rates After Primary Palatoplasty

2021 ◽  
pp. 105566562199265
Author(s):  
Ishwarya Shradha Mamidi ◽  
Esperanza Mantilla-Rivas ◽  
Brynne A. Ichiuji ◽  
Md Sohel Rana ◽  
Karen I. Ramirez ◽  
...  
Keyword(s):  
Single Dose ◽  
Fistula Formation ◽  
Readmission Rates ◽  
Oronasal Fistula ◽  
Inadequate Sample Size ◽  
Perioperative Antibiotics ◽  
The Difference ◽  
Group 2 ◽  
National Databases ◽  
Group 1

Objective: Oronasal fistula (ONF) is a known complication after primary palatoplasty (PP). Studies investigating the effect of perioperative antibiotics on fistula rates after PP are limited by inadequate sample size or reliance on self-reporting through national databases. In this study, the authors evaluated the association between single-dose perioperative antibiotics and postoperative fistula rates after PP at a single institution. Design: A retrospective study. Participants: Children younger than 2 years who underwent PP from April 2009 to September 2019 were included. Interventions: Patients were divided into 2 categories: Group 1 received a single intraoperative dose of IV antibiotic, while group 2 did not. Main Outcome Measure(s): Outcome measures included ONF formation, length of stay (LOS), and 30-day readmission rates. Multivariable firth logistic regression, quantile regression, and χ2 tests were performed. Results: Of the 424 patients, 215 and 209 patients were in groups 1 and 2, respectively. The overall ONF rate was 1.9% among all patients. Patients in group 1 experienced an ONF rate of 3.3%, while patients in group 2 had an ONF rate of 0.5%. After correcting for confounding variables, the difference in ONF rates was not statistically different ( P = .68). Median LOS was 35.7 hours and 35.5 hours ( P = .17), while the rate of readmission within 30 days was 4.7% and 2.4% for group 1 and 2, respectively ( P = .96). Conclusions: Administration of a single-dose perioperative antibiotic did not decrease fistula formation after PP, nor did it affect the patient’s LOS or 30-day readmission rate.

A volumetric three-dimensional evaluation of invasiveness of an endoscopic and microscopic approach for transmeatal visualisation of the middle ear

2021 ◽  
pp. 1-5
Author(s):  
A H A Baazil ◽  
J G G Dobbe ◽  
E van Spronsen ◽  
F A Ebbens ◽  
F G Dikkers ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Middle Ear ◽  
Three Dimensional ◽  
Endoscopic Approach ◽  
Microscopic Approach ◽  
Significant Difference ◽  
Computed Tomography Scans ◽  
The Difference ◽  
Group 2 ◽  
Group 1

Abstract Objective This study aimed to compare the necessary scutum defect for transmeatal visualisation of middle-ear landmarks between an endoscopic and microscopic approach. Method Human cadaveric heads were used. In group 1, middle-ear landmarks were visualised by endoscope (group 1 endoscopic approach) and subsequently by microscope (group 1 microscopic approach following endoscopy). In group 2, landmarks were visualised solely microscopically (group 2 microscopic approach). The amount of resected bone was evaluated via computed tomography scans. Results In the group 1 endoscopic approach, a median of 6.84 mm3 bone was resected. No statistically significant difference (Mann–Whitney U test, p = 0.163, U = 49.000) was found between the group 1 microscopic approach following endoscopy (median 17.84 mm3) and the group 2 microscopic approach (median 20.08 mm3), so these were combined. The difference between the group 1 endoscopic approach and the group 1 microscopic approach following endoscopy plus group 2 microscopic approach (median 18.16 mm3) was statistically significant (Mann–Whitney U test, p < 0.001, U = 18.000). Conclusion This study showed that endoscopic transmeatal visualisation of middle-ear landmarks preserves more of the bony scutum than a microscopic transmeatal approach.

scholarly journals Analyzing Dependent Variables with Multiple Surrogates in Accounting Research

2018 ◽  
Author(s):  
Enyi Enyi
Keyword(s):  
Logistic Regression ◽  
Regression Analysis ◽  
Performance Studies ◽  
Geometric Mean ◽  
A Priori ◽  
Geometric Means ◽  
Canonical Correlations ◽  
Dependent Variables ◽  
Actual Outcome ◽  
Ethical Clearance

The paper contains details a research carried out to show that the use of geometric mean to unify multivariate dependent variables in financial performance studies gives better and more practical results than the multiple abstraction analysis provided using advanced econometric tools such as TLS, PLS, MCA, Canonical correlations etc.<div>The study used the logistic regression analysis to compare the a priori expectations of 30 Ph.D research theses with their actual outcomes using econometric tools and the actual outcome using geometric means. The study used Ph.D theses in accounting and finance sourced from the libraries of four universities in Nigeria.</div><div>The study was a desktop research using publicly available literary resources and as such requires no ethical clearance.</div>

scholarly journals Neuropsychological development of children with biliary atresia after liver transplantation

2021 ◽  
Vol 23 (3) ◽  
pp. 66-72
Author(s):  
A. V. Syrkina ◽  
I. E. Pashkova ◽  
A. R. Monakhov ◽  
O. V. Silina ◽  
E. V. Chekletsova ◽  
...  
Keyword(s):  
Liver Transplantation ◽  
Surgical Treatment ◽  
Biliary Atresia ◽  
Psychomotor Development ◽  
Two Stage ◽  
Neuropsychological Development ◽  
One Stage ◽  
The Difference ◽  
Group 2 ◽  
Group 1

Background. In young children, the most common liver disease leading to transplantation is biliary atresia. Liver transplantation has fundamentally improved the survival rate of children with biliary atresia. Studies on developmental outcomes in children are mostly limited to small samples; there are no such studies in the Russian Federation.Objective: to determine the cognitive outcomes in children undergoing one-stage or two-stage surgical treatment of biliary atresia.Materials and Methods. 83 children were divided into groups: 36 children underwent transplantation without previous surgical interventions (group 1), 47 children underwent the Kasai palliative portoenterostomy (group 2). Inclusion criteria: 24 months of age or younger at the moment of transplantation, no medical history of neurological pathology. All children were examined before transplantation and at 1, 3, 6 and 12 months after liver transplantation. Psychomotor development was assessed using the Griffiths Psychomotor Development Scale for children under 24 months (translated by E.S. Keshishian), the Griffiths Intellectual Development Scale for children aged 2 to 8 years, and the Modified Checklist for Autism in Toddlers, Revised, for children 16-30 months old.Results. All children had developmental delays at the time of transplantation. Up to 50% of the children had signs of cachexia, with a shoulder circumference of less than 3 percentile. Only two children showed obvious hepatic encephalopathy in the form of depressed consciousness. After liver transplantation, 94% of group 1 children recovered their preoperative psychomotor development levels, and only 68% in group 2 made these gains. At 3 and 6 months after transplantation, about 80% of group 1 children showed normal psychomotor development, whereas in group 2, only 61% did. By 12 months after liver transplantation, the difference between the groups was more evident: 83.3% of group 1 children and only 53.2% of group 2 children were developing according to age. The difference between the groups was statistically significant (p < 0.05).Conclusion. Children who received one-stage treatment of biliary atresia and underwent liver transplantation have better neuropsychological development within a year after surgery than children with two-stage surgical treatment.

scholarly journals Accelerated versus conventional Ponseti protocol for the treatment of idiopathic talipes equinovarus deformity: A short term follow up in Iraq

2021 ◽  
Vol 25 (1) ◽  
pp. 473-479
Author(s):  
Jagar Doski ◽  
Berivan Jamal
Keyword(s):  
Ponseti Method ◽  
Congenital Talipes Equinovarus ◽  
Talipes Equinovarus ◽  
The Mean ◽  
Congenital Talipes ◽  
The Difference ◽  
Group 2 ◽  
Accelerated Protocol ◽  
Group 1

Background and objective: The accelerated protocol of Ponseti method was suggested to shorten the period of treatment of the conventional one for the cases of talipes equinovarus deformity. This study aimed to compare the accelerated protocol of Ponseti method in the treatment of clubfoot deformity with the conventional one. Methods: A prospective comparative study was conducted for infants less than six months with congenital talipes equinovarus deformity. The patients were randomized to either Group 1 (casts changed every week, conventional protocol of Ponseti method) or Group 2 (twice weekly, accelerated one). Pirani score was used to assess the severity of the deformity at presentation, at time of last cast removal, and at the last follow up visit (6th months). Results: The patients included were 48 cases with 79 feet. Group 1 (39 clubfeet) had a mean Pirani score of 5.6 (± 1.15) at presentation, which dropped to 0.47 (± 0.41) when the last cast was removed. In Group 2 (40 clubfeet), it dropped from 5.57 (± 0.83) to 0.77 (± 0.01). The result of each treatment protocol was significant, but the difference between them was not significant. Five cases (three patients aged more than three months) of Group 2 needed eight casts to reach an acceptable position of correction. The difference between the mean number of casts applied in Group 1 (5.09) and Group 2 (5.82) was statistically not significant. However, the difference between the mean number of days spent in the cast was significant. The complications occurred in 12 out of 79 feet, with no statistically significant difference between both groups. Conclusion: The accelerated protocol of Ponseti method for treating clubfoot deformity is as effective and as safe as the conventional one. It shortens the time required to complete the treatment program. Those who present lately (beyond the age of three months) may require an additional number of casts. Keywords: Clubfoot; Congenital talipes equinovarus; Ponseti; Accelerated; Cast.

scholarly journals The Impact of Switching from Short-Term Teriparatide Treatment to Denosumab Therapy Compared with Denosumab Alone for Patients with Osteoporotic Hip Fracture: A 1-Year Follow-up Study

2020 ◽  
Author(s):  
Chan Ho Park ◽  
Jun-Il Yoo ◽  
Chang Hyun Choi ◽  
You-Sung Suh
Keyword(s):  
Hip Fracture ◽  
Mineral Density ◽  
Short Term ◽  
Short Term Treatment ◽  
T Score ◽  
The Difference ◽  
Group 2 ◽  
The Impact ◽  
Group 1

Abstract Background: Switching the prescription from bone-forming medication to resorptive agents is reportedly effective for patients with severe osteoporosis. The objective of this study is to determine the impact of implementing short-term teriparatide (TPTD) intervention before denosumab (DMab) therapy compared with DMab therapy alone for 1 year after hip fracture.Methods: TPTD was administered to 24 patients for an average of 12.1 weeks after which the intervention was switched to DMab therapy for 12 months (group 1). DMab alone was administered to 16 patients for 12 months (group 2). Bone mineral density (BMD) was evaluated before and after treatment at the 1-year follow-up. The improvement of BMD and T-score in hip and spine was compared with the levels of bone turnover marker.Results: The difference of hip BMD after osteoporosis treatment was -0.0081±0.03 in group 1 and 0.0074±0.04 in group 2 (p=0.180). The difference of spine BMD was 0.0819±0.04 in group 1 and 0.0145±0.03 in group 2 (p<0.001). BMD and T-score of the spine improved significantly in groups 1 and 2 (p < 0.001). There was no statistical difference in C-terminal telopeptide and osteocalcin level. Conclusion: Short-term TPTD administration followed by DMab alone was effective only in improving spine BMD. Short-term treatment with TPTD caused mild improvement in femur neck BMD compared with DMab alone. However, further research with a longer duration of TPTD treatment is warranted, as our findings lack statistical significance.

scholarly journals The difference in outcome of patients with open inguinal hernia repair by using delayed absorbable sutures instead of non-absorbable sutures for mesh fixation

2020 ◽  
Vol 8 (1) ◽  
pp. 24
Author(s):  
Ali G. Mohammed Redha ◽  
Adil A. Jaber ◽  
Aqeel M. Nasser
Keyword(s):  
Hernia Repair ◽  
Mesh Fixation ◽  
Good Alternative ◽  
P Value ◽  
Absorbable Sutures ◽  
Significant Difference ◽  
The Difference ◽  
Group 2 ◽  
One Year ◽  
Group 1

Background: Different methods are found for mesh fixation in inguinal hernioplasty both open and laparoscopic. In open technique, sutures have been the method of choice for their reduced costs and surgeons’ habits. Whether absorbable instead of non-absorbable sutures can be used still a matter of debate in view of hernia recurrence and post-operative complications.Methods: This is a prospective done on 158 male patients with uncomplicated unilateral inguinal hernias. Two groups of 69 patients were evaluated after periods up to 1 year after open hernioplasty by using delayed absorbable sutures in one group (group 1) and non-absorbable sutures in the other group (group 2) for fixation of mesh.Results: In spite of a noticeable reduction in complication in the group 1 in term of number and percentage when compared with group 2 mainly chronic pain, there is no significant difference (p value>0.05). However, these results are associated with zero recurrence in both groups during a period of one year follow up.Conclusions: Delayed absorbable sutures are good alternative of non-absorbable sutures in open mesh hernia repair associated with less complications and almost no increase in chance of recurrence.  

scholarly journals Comparison of Inflammatory Reactions Following Two Different Cesarean Section Techniques: The Modified Misgav-Ladach Versus the Pfannenstiel-Kerr; A Prospective Randomized Trial

2018 ◽  
pp. 1
Author(s):  
Baris Buke ◽  
Hatice Akkaya ◽  
Cigdem Karakukcu
Keyword(s):  
Cesarean Section ◽  
Inflammatory Reaction ◽  
Operation Time ◽  
Blood Samples ◽  
Inflammatory Reactions ◽  
Tnf Α ◽  
Significant Difference ◽  
The Difference ◽  
Group 2 ◽  
Group 1

<p><strong>Objectives:</strong> There is not yet a consensus on the optimal surgical technique for cesarean section. This is the first study comparing two different (Cesarean Section) with respect to the following inflammatory reaction in means of changes in inflammatory marker levels.<br />To evaluate the differences in inflammatory reactions following two different (Cesarean Section) techniques, the modified Misgav-Ladach versus the Pfannenstiel-Kerr technique.</p><p><strong>Study Desıgn:</strong> The study population included 88 pregnant women who met the inclusion criteria. These women were randomized into two groups according to Consolidated Standards of Reporting Trials guidelines: Group 1 (Misgav-Ladach group) and Group 2 (Pfannenstiel Kerr group). To compare the inflammatory reactions following surgery, Interleukin-6 (IL-6) and Tumor Necrosis Factor-α (TNF-α) levels were measured in venous blood samples drawn from the patients just before (0 hour) and 24 hours (24th hour) after the surgery. In 5 women from Group 1 and 2 women from Group 2, the 24th hour blood samples could not be obtained or were lost. Thus, a total of 81 women, 39 women from Group 1 and 42 women from Group 2, comprised the population of study. The differences in inflammatory reactions between the 0 and 24th hours were analyzed by calculating the percent change in IL-6 and TNF-α levels, and these percentages were then compared between the groups.</p><p><strong>Results:</strong> There was a statistically significant difference between Group 1 and Group 2 regarding the serum IL-6 level change between 0 and 24th hour (530±653% and 196±168%, respectively, p=0.022. The difference in TNF-α was also higher in Group 2, but the difference was not statistically significant (229±306% vs. 571±824%, p=0.12). The mean operation time was significantly shorter in Group 1 (9.44 min. vs. 16.86 min, p=0.0001).</p><p><strong>Conclusions:</strong> The results of this study indicate that the modified Misgav-Ladach technique has a weaker inflammatory reaction, which indicates fewer short- and long-term surgical complications.</p>

scholarly journals The Effectiveness of Endoscopic Surgery of Juvenile Angiofibroma Using Surgical Glue

2020 ◽  
Vol 8 (B) ◽  
pp. 150-154
Author(s):  
Seyed-Hadyi Samimi Ardesan ◽  
Mojtaba Mohammadi Ardehali ◽  
Najmeh Doustmohammadian
Keyword(s):  
Blood Loss ◽  
Endoscopic Surgery ◽  
Tumor Staging ◽  
Low Cost ◽  
Tumor Stage ◽  
Nasopharyngeal Angiofibroma ◽  
Group 3 ◽  
The Difference ◽  
Group 2 ◽  
Group 1

AIM: The current study aimed to provide a method for juvenile nasopharyngeal angiofibroma embolization using Glubran glue in patients with low stage tumor. This method not only has less blood loss and good visualization but also impose a low cost, where no pre-operative embolization complications were found for this procedure. METHODS: Between 2012 and 2014, 30 patients with angiofibroma undergoing endoscopic surgery. Age, sex, tumor stage, average blood loss, complications, length of hospitalization, and recurrence rate of the tumor were the main measured outcomes. Furthermore, 30 patients were divided into three groups with matched age, sex, and tumor staging. Group 1 received glue (Glubran), while Group 2 selected for study without glue and embolization and pre-operative embolization was considered for Group 3. RESULTS: Based on the amount bleeding, the mean blood hemorrhage in Groups 1, 2, and 3 was 510, 1655, and 800 ml, respectively, the difference of hemorrhage between Groups 1 and 2 was found to be statistically significant (p = 0.007). Blood loss in Group 1 was found to be less than Group 3, but the difference of hemorrhage between Group 1 and 3 was not statistically significant (p = 0.678). No blood transfusion and complication were recorded for individuals in Group 1. The recurrence was found in 1 patient (10%) in both groups of 2 and 3, and no patient (0%) in Group 1. CONCLUSIONS: The direct intraoperative embolization technique with glue was capable of providing a more complete and targeted embolization of the tumor. Some advantages can be mentioned for this technique, including decreased blood loss, less radiation exposure, lower rates of complications, and recurrence, as well as shorter hospitalization time, the ease of procedure with a spinal needle and low cost.

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