Sample size: how many participants do I need in my research?

Martínez-Mesa, Jeovany; González‐Chica, David Alejandro; Bastos, João Luiz; Bonamigo, Renan Rangel; Duquia, Rodrigo Pereira

doi:10.1590/abd1806-4841.20143705

Cited by 131 publications

(93 citation statements)

References 3 publications

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“…Further, the scores of both measures were correlated, suggesting that the more frequent their orofacial dysfunction, the greater the impairment of QoL in both populations. The strengths of this study include an a priori sample size calculation, as this is an essential item to reduce the probability of error 26 , and matching controls by age and sex, which allowed for the homogeneous distribution of these variables in the groups. Another strength of this investigation was the use of standardized questionnaires and also the standardized assessment of the oral conditions by a single calibrated/trained examiner.…”

Section: Discussionmentioning

confidence: 99%

Orofacial functions and quality of life in children with unilateral cleft lip and palate

et al. 2019

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This study aimed to evaluate the orofacial functions and oral health-related quality of life (OHRQoL) of children with unilateral cleft lip and palate (UCLP). This case-control study included patients with UCLP matched by sex and age with controls (children without UCLP), resulting in the inclusion of a total of 108 eight-to ten-year-old children. Orofacial functions and OHRQoL were evaluated using the Nordic Orofacial Test-Screening (NOT-S) and the Child Perceptions Questionnaire (CPQ 8-10 ), respectively. Data normality was assessed by the Kolmogorov-Smirnov test. Differences and correlations in NOT-S and CPQ 8-10 scores between and within the groups were evaluated using Mann-Whitney and Spearman´s correlation tests, respectively. The distribution of NOT-S and global ratings of CPQ 8-10 for each group were assessed by Chi-squared/Fisher's Exact tests. The UCLP group had a higher NOT-S total and examination scores than the controls. Dysfunctions related to breathing, facial symmetry/expression, and speech were more frequent in the UCLP patients than in the controls. The UCLP group had higher scores on the social well-being domain than the controls. There was a significant difference between the groups in their ratings in regards to the extent to which their oral condition affected their life overall, with controls perceiving it as somewhat better than patients. In both groups, NOT-S total and interview scores were positively correlated with CPQ 8-10 total and domain scores. The NOT-S examination score was only significantly correlated with social domain scores in the control group. The presence of UCLP was associated with clinical signs of orofacial dysfunctions related to breathing, facial symmetry/expression, and speech. Children with UCLP reported more orofacial dysfunctions and negative impacts on social well-being than controls.

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Section: Discussionmentioning

confidence: 99%

Orofacial functions and quality of life in children with unilateral cleft lip and palate

et al. 2019

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“…But in our meta-analysis, the results were just the reverse. In fact, there are two critical factors influencing the results of subgroup analyses: one is the limited sample volume in this research [41]; the other may be the general pathway existing in the various subtypes of NDs, in which the miRNAs selected are just involved.…”

Section: Discussionmentioning

confidence: 99%

Circulating MicroRNA as Potential Source for Neurodegenerative Diseases Biomarkers

Yin

Xiao

et al. 2014

Mol Neurobiol

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An increasing number of circulating micro-ribonucleic acids (microRNAs, miRNAs) have been discovered its potential as biomarkers to diagnose neurodegenerative diseases (NDs) by many researchers. However, there were obvious inconsistencies among previous studies, and thus we performed this meta-analysis to evaluate whether miRNA is an effective biomarker with high accuracy to diagnose the NDs. PubMed, MEDLINE, EMBASE, the Cochrane Library, and other related databases were used to search eligible articles. The data of sensitivity and specificity were employed to plot the summary receiver operator characteristic (SROC) curve and calculate the area under the SROC curve (AUC). I (2) test were used to estimate the heterogeneity among different studies. In addition, the possible sources of heterogeneity were further explored by subgroup analyses and meta-regression. All analyses were performed by STATA 12.0 software. In this meta-analysis, eight publications with 459 NDs patients and 340 healthy controls were included to investigate the diagnostic performance of circulating miRNAs for NDs. The overall sensitivity and specificity, positive likelihood ratio (PLR), negative likelihood ration (NLR), and diagnostic odds ratio (DOR) were 0.83 (95% confidence interval (CI) 0.77-0.88), 0.87 (95% CI 0.83-0.89), 6.2 (95% CI 4.9-7.9), 0.19 (95% CI 0.14-0.27), 33 (95% CI 20-52), and 0.91 (95% CI: 0.88-0.93), respectively. The overall SROC curve was plotted with AUC of 0.91 (95% CI 0.88-0.93), which indicated an excellent diagnostic performance of circulating miRNA for NDs. Subgroup analysis based on miRNA profile demonstrated that multiple-miRNA assay had higher diagnostic accuracy for NDs when compared with single-miRNA assay. In conclusion, the circulating miRNAs may be the potential biomarkers in the clinical diagnosis of NDs, and the diagnostic accuracy would be better by using multiple-miRNA assay. However, large-scale studies are still needed to explore the relation between the circulating miRNA dysregulation and the pathological mechanism of NDs.

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“…Primary research was conducted using the self-administered research questionnaires that were given to a sample size of six hundred (600) members of stokvels to fill in. In support of Martinez-Mesa et al (2014) argument, the larger sample size is normally associated with greater precision. It is against this backdrop that the current study chose a sample size of 600 respondents.…”

Section: Methodsmentioning

confidence: 96%

Characteristics of Credit Instruments Issued by Stokvels in South Africa

Ngcobo¹,

Chisasa²

2018

JEBS

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Access to formal credit and other financial instruments remains a challenge for the majority of households in South Africa. The objective of this study was, therefore, to determine the characteristics of credit instruments issued by stokvels to households in South Africa. Prior studies have generally focused on mobilization of savings through stokvels while none has paid particular attention to the credit supply function of stokvels. This study attempts to fill this gap by using a self-administered research questionnaire on a sample of 386 respondents. Members of stokvels were surveyed from the cities of Pretoria and Johannesburg in the Gauteng province of South Africa. Data was analysed using descriptive statistics, exploratory factor and correlation analyses. Results show that stokvels issue short-term loans from less than 3 to 6 months. Interest rates are high ranging from 25% to 35% and are charged monthly. Loan sizes are small with approximately two-thirds of the respondents receiving loans above R500 while the remaining third received less than R500. Finally, all loans are secured by the borrower's identification document or bank card and personal identification number. The results of this study have policy implications for financial institutions in South Africa.

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Sample size: how many participants do I need in my research?

Cited by 131 publications

References 3 publications

Orofacial functions and quality of life in children with unilateral cleft lip and palate

Orofacial functions and quality of life in children with unilateral cleft lip and palate

Circulating MicroRNA as Potential Source for Neurodegenerative Diseases Biomarkers

Characteristics of Credit Instruments Issued by Stokvels in South Africa

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