scholarly journals A Robust Bootstrap Test for Mediation Analysis

2021 ◽  
pp. 109442812199909
Author(s):  
Andreas Alfons ◽  
Nüfer Yasin Ateş ◽  
Patrick J. F. Groenen

Mediation analysis is central to theory building and testing in organizational sciences. Scholars often use linear regression analysis based on normal-theory maximum likelihood estimators to test mediation. However, these estimators are very sensitive to deviations from normality assumptions, such as outliers, heavy tails, or skewness of the observed distribution. This sensitivity seriously threatens the empirical testing of theory about mediation mechanisms. To overcome this threat, we develop a robust mediation method that yields reliable results even when the data deviate from normality assumptions. We demonstrate the mechanics of our proposed method in an illustrative case, while simulation studies show that our method is both superior in estimating the effect size and more reliable in assessing its significance than the existing methods. Furthermore, we provide freely available software in R and SPSS to enhance its accessibility and adoption by empirical researchers.

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Wanqin Feng ◽  
Yan Zhang ◽  
Yuan Pan ◽  
Yi Zhang ◽  
Minjuan Liu ◽  
...  

Abstract Background The etiology between homocysteine and polycystic ovary syndrome (PCOS) is unclear. In humans, the level of homocysteine is mainly affected by two enzymes: methylene tetrahydrofolate reductase (MTHFR) and methionine synthase reductase (MTRR). While the activity of these two enzymes is mainly affected by three missense mutations, namely C677T (MTHFR), A1298C (MTHFR), and A66G (MTRR). This study aims to examine the association between the three missense mutations and PCOS and investigate whether the three missense mutations exerted their effect on PCOS by affecting the homocysteine level. Methods A case-control study was designed, comprising 150 people with PCOS and 300 controls. Logistic regression analysis was used to assess the association between the three missense mutations and PCOS. Linear regression analysis was used to assess the association between the three missense mutations and the homocysteine level. Mediation analysis was used to investigate whether the three missense mutations exerted their effect on PCOS by affecting the homocysteine level. Results Following adjustments and multiple rounds of testing, MTHFR A1298C was found to be significantly associated with PCOS in a dose-dependent manner (compared to AA, OR = 2.142 for AC & OR = 3.755 for CC; P < 0.001). MTRR A66G was nominally associated with PCOS. Mutations in MTHFR A1298C and MTRR A66G were significantly associated with the homocysteine level. Mediation analysis suggested the effect of MTHFR A1298C on PCOS was mediated by homocysteine. Conclusions MTHFR A1298C and MTRR A66G were associated with PCOS, and MTHFR A1298C might affect the risk of PCOS by influencing the homocysteine level.


2003 ◽  
Vol 1 (1) ◽  
pp. 91-102 ◽  
Author(s):  
Steve E. Shive ◽  
Michelle R. Neyman

This study examined fruit intake among 276 female Extended Opportunity Program and Services (EOPS) community college students. Knowledge, attitudes, and behaviors associated with fruit intake were determined. The attitudes which are potential predictors of daily fruit intake were also examined. Analysis showed that 33% ate fewer than the minimum recommended two daily servings of fruit. Students reported that fruit gave them energy, taste and cost were not barriers to consumption and that it would not be difficult to increase daily fruit consumption. A linear regression analysis revealed that beliefs that eating fruit leads to good health, having a habit of eating fruit, feeling energy, and weight loss accounted for 30% of the variance in fruit intake.


Author(s):  
Muhammad Rois Rois ◽  
Manarotul Fatati Fatati ◽  
Winda Ihda Magfiroh

This study aims to determine the effect of Inflation, Exchange Rate and Composite Stock Price Index (IHSG) to Return of PT Nikko Securities Indonesia Stock Fund period 2014-2017. The study used secondary data obtained through documentation in the form of PT Nikko Securities Indonesia Monthly Net Asset (NAB) report. Data analysis is used with quantitative analysis, multiple linear regression analysis using eviews 9. Population and sample in this research are PT Nikko Securities Indonesia. The result of multiple linear regression analysis was the coefficient of determination (R2) showed the result of 0.123819 or 12%. This means that the Inflation, Exchange Rate and Composite Stock Price Index (IHSG) variables can influence the return of PT Nikko Securities Indonesia's equity fund of 12% and 88% is influenced by other variables. Based on the result of the research, the variables of inflation and exchange rate have a negative and significant effect toward the return of PT Nikko Securities Indonesia's equity fund. While the variable of Composite Stock Price Index (IHSG) has a negative but not significant effect toward Return of Equity Fund of PT Nikko Securities Indonesia


Liquidity ◽  
2018 ◽  
Vol 1 (2) ◽  
Author(s):  
Yanti Budiasih

The objectives of this study are to analyze changes in organizational structure, job design, organizational culture and its influence on employee productivity at PT. XX in Jakarta and to identify variables that have a dominant influence on the productivity of employees. The research method used is using multiple linear regression analysis. The results show that the all variables simultaneously and partially change the organizational structure, job design, and organizational culture has a significant impact on employee productivity at PT. XXin Jakarta.


10.32698/0642 ◽  
2019 ◽  
Vol 2 (2) ◽  
pp. 120
Author(s):  
Wiwi Delfita ◽  
Neviyarni S. ◽  
Riska Ahmad

Some students perceive lesbian, gay, bisexual, and transgender (LGBT) positively, even though LGBT is a sexual deviation that is not appropriate with values and norms. There are several factors that influence an individual's perception of LGBT, including sexual identity. This study aims at looking at the contribution of sexual identity to student perceptions about LGBT. This research used a quantitative approach with a descriptive method and a simple linear regression analysis. The sample of this research was 385 taken from 15.752 undergraduate students of Universitas Negeri Padang which the sample was drawn by using the Slovin formula and continued with a Proportional Random Sampling technique. The instrument used was the Guttman model's sexual identity scale and the scale of students' perceptions of the LGBT Likert model. After analyzing the data with the descriptive technique and the simple linear regression analysis, the results showed that sexual identity significantly contributed to the students' perceptions of LGBT. This research has implications as a basis for counselors to help students avoid sexual identity mismatches and prevent the emergence of positive perceptions of LGBT.


MBIA ◽  
2019 ◽  
Vol 18 (1) ◽  
pp. 76-84
Author(s):  
Muhammad Idris ◽  
Dian Novita Sari

The problem in this study is whether there is an influence of leadership and work discipline on the employees’ performance of PT.Sucofindo Palembang City. This research includes associative research. The sample in this study were 88 respondents, with propotionate random sampling analysis technique. The data used were primary data and secondary data. Data collection method through questionnare. Analysis techniques using multiple linear regression analysis, F test (Simultaneoys) and t test (partial) and determination coeffiecient. The results show that there is influence of leadership and work discipline on the performance of PT.Sucofindo Palembang City.


2017 ◽  
Vol 4 (1) ◽  
pp. 189-215
Author(s):  
Yoiz Shofwa Shafrani

Perkembangan dunia perbankan syariah tidak lepas dari peran para nasabah yang memberikan kepercayaan terhadap pihak perbankan untuk penyimpanan asset keuangannya. Faktanya banyak kelompok nasabah yang memutuskan untuk menjadi nasabah di perbankan syariah karena faktor religiusitasnya. Faktor lain yang dapat ikut mempengaruhi keputusan nasabah adalah kualitas produk. Di mana kualitas produk merupakan karakteristik yang melekat dari suatu produk. Kemungkinan yang terjadi bahwa kebanyakan nasabah pada perbankan syariah juga masih merupakan nasabah perbankan konvensional.Tujuan yang ingin dicapai dalam penelitian ini adalah untuk mengetahui pengaruh kualitas produk dan tingkat religiusitas nasabah terhadap keputusan nasabah untuk menyimpan dananya atau tidak di BSM Cabang Purwokerto. Alat analisis yang digunakan adalah analisis regresi linier berganda, dengan jumlah sampel 100 nasabah. Diperoleh hasil Y = 5,046 + 0,101X1 + 0,218X2. Berdasarkan uji F yang sudah dilakukan maka dapat diketahui bahwa variabel kualitas produk dan religiusitas secara bersama – sama berpengaruh terhadap keputusan nasabah untuk menyimpan dananya di BSM Cabang Purwokerto. Berdasarkan uji t yang sudah dilakukan dapat diketahui bahwa secara partial baik variabel kualitas produk maupun variabel religiusitas berpengaruh terhadap keputusan nasabah untuk menyimpan dananya di BSM Cabang Purwokerto. The progress of the Islamic bank cannot be separated from the role of its customers who give trust to the bank to deposit their financial assets. It is a fact many groups of customers decide to be the customers of the Islamic bank because of their religiosity. The other influences factor of a customer’s decision is the quality of the product. The aim of this research was to determine the effect of product quality and level of customers’ religiosity towards customers’ decision whether to keep their funds in Syariah Mandiri Bank, Branch of Purwokerto, or not. The analytical tool used was multiple linear regression analysis, with a sample of 100 customers. The results indicate Y = 5,046 + 0,101X1 + 0,218X2. Based on F, it can be seen that both variables of product quality and religiosity simultanously affect the customers’ decision to keep theirfunds in BSM Branch of Purwokerto. Based on t test, it can be seen that independently, either variable of product quality or variables of religiosityinfluences the customers’ decision to keep their funds in BSM Branch of Purwokerto.


2019 ◽  
Vol 13 (2) ◽  
pp. 199
Author(s):  
Asrye Tutur Sinaga ◽  
Nurul Wardani

AbstrakPenelitian ini bertujuan untuk mengetahui dan dapat menjelaskan pengaruh Kualitas Pelayanan dan Word Of Mouth terhadap Keputusan pembelian di Kafe Potret Medan. Populasi dalam penelitian ini adalah 700 orang ditentukan dari jumlah pengunjung Kafe Potret Medan dalam kurun waktu satu minggu, dan sampel yang digunakan berjumlah 88 pengunjung. Sedangkan tehnik pengumpulan data menggunakan angket (kuesioner) dan pengujiannya yaitu uji kualitas data dan uji asumsi klasik.Pengujian hipotesis menggunakan analisis regresi linier berganda, uji F, uji t, dan uji R2. Hipotesis penelitian dimensi Kualitas Pelayanan dan Word Of Mouth secara parsial terhadap Keputusan Pembelian diterima jika t hitung > t tabel dengan tingkat signifikan 0.05.Nilai t tabel dalam penelitian ini 1,662. Nilai t hitung variabel X1 sebesar 1,990 t hitung  > t tabel maka hipotesis diterima, nilai t hitung variabel X2 sebesar 2,628 t hitung > t tabel maka hipotesis diterima. Dari 2 variabel, variabel Word Of Mouth yang paling dominan mempengaruhi Keputusan Pembelian  sebesar 2,628. Kata Kunci : Kualitas Pelayanan, Word Of Mouth, Keputusan Pembelian AbstractThe purpose of this study is to identify and able to explain the influence of Service Quality and Word Of Mouth to Purchasing Decisions of Kafe Potret Medan. The population in this study were 700 people from visitors Kafe Potret Medan in one week, and the samples used were 88 visitors. While the techniques of data collection using the questionnaire and use the test of quality data and classical assumption. The hypothesis test uses multiple linear regression analysis, F test, R square and t test. The study hypothesis was partially of Service Quality and Word Of Mouth dimension to  Purchasing Decisions is acceptable if t hitung > t tabel with a significant level 0.05. The t tabel value in this study 1.662. The t hitung X1 is 1.990 that mean t hitung > t tabel then the hypothesis is accepted, t hitung X2 is 2.628 that mean t hitung > t tabel then the hypothesis is accepted. From 2 variables fascination that the most dominant variable for Purchasing Decisions is Word Of Mouth of 2.628. Keywords : Service Quality, Word Of Mouth, Purchasing Decisions


2020 ◽  
Vol 16 (3) ◽  
pp. 292
Author(s):  
Marfunizah Ma'dan ◽  
Muhamad Takiyuddin Ismail ◽  
Sity Daud

Intensity to produce a quality human capital is not sufficient by having basic skills for certain field only. The need to have a competitive attitude to enhance their level of competency is much concern for many employers nowadays. Hence, this study is conducted to identify the competitiveness factors that influence the level of competency among graduates, especially who employed in the service sector in Malaysia. This study used survey methods by distributing questionnaires for data collection. The study used stratified purposive sampling by distributing a questionnaire to 450 graduates from 13 services sectors based on a statistic from the Ministry of Higher Education 2016. The finding from the exploratory factor analysis found that seven competitiveness factors were consisting of 47 items that form the competitiveness attitude among graduates. However, based on multiple linear regression analysis, only five models of competitiveness factors have a significant relationship with graduates’ competency which are job competitiveness, organizational management competitiveness, dominant competitiveness, goal competitiveness and self-improvement competitiveness. In fact, aggressive competitiveness and general competitiveness does not influence graduates’ competency level significantly. Thus, the more competitive attitude of graduates such as emotional control, innovation, and competitiveness to be the best is vital for their future marketability. In addition, it is hoped that their level of competence can be enhanced through the development of competitive factors for the advancement of the country's higher education talent.


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