Descriptive and inferential statistical methods used in burns research

Neutrophil to lymphocyte ratio is predictive of severe complications and mortality in patients with dipeptidyl peptidase-4 inhibitor-associated bullous pemphigoid: A retrospective longitudinal observational study

Hypothesis tests

Introduction. Research on celiac disease is based on a descriptive and inferential variety of techniques that allow summarizing data and extrapolating the target population. The aim of this study was to identify descriptive and inferential statistical methods used in International Journal of Celiac Disease. Material and method. The sample of this study was defined based on all original articles published in the journal mentioned above in 2013- 2014 period. We evaluated the descriptive statistics, the number and type of inferential statistical methods used. Results. Of the eight articles analyzed, one study was a randomzat clinical trial, the remaining studies were cross- sectional studies. The articles have used both quantitative and qualitative data. The indicator of central tendency on data was mean (n = 5, 62.5 %) or the median with interquartile range (n = 1, 12.5 %) and the dispersion of data was estimatedonly by the standard deviation in 5 studies (62.5 %). Quantitative data were used in raw form, except for one study using Z scores. Qualitative data were summarized using absolute and relative frequencies (n = 7, 87.5 %). The statistical software was mentioned in all studies. All articles except one used the inferential statistical methods or statistical tests. Most articles (87.5 %) used common tests as Student's t- test (37.5), analysis of variance/covariance (25 %), Kruskal -Wallis test (12.5 %), χ2 test (50 %), and Fisher's exact test (12.5 %). A specified significance level was noted in 62.5 % of the articles and the significance level was estimated in 6 studies (75 %). Conclusion. Results showed that a proper understanding of standard statistical methods leads to a proper interpretation of clinical research hypothesis. If necessary, the advanced statistical analysis should be performed by a multidisciplinary collaboration with specialists in biostatistics or epidemiology.

To determine whether a single outpatient dose of intravaginal misoprostol (versus intracervical dinoprostone gel) reduces the oxytocin use for induction. Despite the numerous trials examining misoprostol for induction, the efficacy of a single outpatient dose of misoprostol followed by oxytocin induction is unknown. Patients with a term, vertex, singleton pregnancy and a Bishop score of 6 or less were randomly assigned to receive misoprostol (n = 42, 0.25 microg intravaginally) or dinoprostone gel (n = 42, 0.5 mg intracervically) the evening before oxytocin induction. Patients were monitored for 3 hours after administration and discharged to home if fetal assessment was reassuring, for readmission the next morning for oxytocin. Primary outcomes were oxytocin dose, time, and dose intensity (dose divided by duration). Secondary outcomes were incidence of labor, uterine hyperstimulation, cesarean delivery, Apgar score. Statistics used were chi(2), Student t test, Mann-Whitney rank sum test, and Fisher exact test. P < .05 was accepted as statistically significant. A single dose of misoprostol significantly decreased the cumulative dose of oxytocin, the cumulative time of oxytocin administration, and the dose intensity of oxytocin (dose divided by time). Data are as follows (mean +/- standard error of the mean): oxytocin dose-dinoprostone 10,929 +/- 219 mU, misoprostol 6,081 +/- 170 mU, P = .008; oxytocin time-dinoprostone 798 +/- 11 minutes, misoprostol 531 +/- 11 minutes, P = .009; dose intensity-dinoprostone 11.3 +/- 0.1 mU/min, misoprostol 7.4 +/- 0.2 mU/min, P = .003. Misoprostol induced labor during the ripening period in 19 of 41 of patients, compared with 6 of 42 after dinoprostone (P = .002). There was no difference in cesarean delivery (dinoprostone, 8/42; misoprostol, 9/42; P = 1.00). There was no difference in short-term neonatal outcome. No patient had hyperstimulation or required cesarean delivery for nonreassuring fetal assessment during the ripening period. A single dose of misoprostol administered in the outpatient setting significantly decreases oxytocin use, largely due to labor within the ripening period.

1. Introduction. Statistics and the Life Sciences. Examples and Overview. 2. Description of Populations and Samples. Introduction. Frequency Distributions: Techniques for Data. Frequency Distributions: Shapes and Examples. Descriptive Statistics: Measures of Center. Boxplots. Measures of Dispersion. Effect of Transformation of Variables (Optional). Samples and Populations: Statistical Inference. Perspective. 3. Random Sampling, Probability, and the Binomial Distribution. Probability and the Life Sciences. Random Sampling. Introduction to Probability. Probability Trees. Probability Rules (Optional). Density Curves. Random Variables. The Binomial Distribution. Fitting a Binomial Distribution to Data (Optional). 4. The Normal Distribution. Introduction. The Normal Curves. Areas Under a Normal Curve. Assessing Normality. The Continuity Correction (Optional). Perspective. 5. Sampling Distributions. Basic Ideas. Dichotomous Observations. Quantitative Observations. Illustration of the Central Limit Theorem (Optional). The Normal Approximation to the Binomial Distribution (Optional). Perspective. 6. Confidence Intervals. Statistical Estimation. Standard Error of the Mean. Confidence Interval. Planning a Study to Estimate. Conditions for Validity of Estimation Methods. Confidence Interval for a Population Proportion. Perspective and Summary. 7. Comparison of Two Independent Samples. Introduction. Standard Error of (y1 - y2). Confidence Interval. Hypothesis Testing: The t-test. Further Discussion of the t-test. One-Tailed Tests. More on Interpretation of Statistical Significance. Planning for Adequate Power (Optional). Student's t: Conditions and Summary. More on Principles of Testing Hypotheses. The Wilcoxon-Mann-Whitney Test. Perspective. 8. Statistical Principles of Design. Introduction. Observational Studies. Experiments. Restricted Randomization: Blocking and Stratification. Levels of Replication. Sampling Concerns (Optional). Perspective. 9. Comparison of Paired Samples. Introduction. The Paired-Sample t-Test and Confidence Interval. The Paired Design. The Sign Test. The Wilcoxon Signed-Rank Test. Further Considerations in Paired Experiments. Perspective. 10. Analysis of Categorical Data. Inference for Proportions: The Chi-Squared Goodness-of-Fit Test. The Chi-Squared Test for a 2 X 2 Contingency Table. Independence and Association in a 2 X 2 Contingency Table. Fisher's Exact Test (Optional). The r x k Contingency Table. Applicability of Methods. Confidence Interval for a Difference Between Proportions. Paired Data and 2 X 2 Tables (Optional). Relative Risk and the Odds Ratio (Optional). Summary of Chi-Squared Tests. 11. Comparing the Means of Many Independent Samples. Introduction. The Basic Analysis of Variance. The Analysis of Variance Model (Optional). The Global F-Test. Applicability of Methods. Two-Way ANOVA (Optional). Linear Combinations of Means (Optional). Multiple Comparisons (Optional). Perspective. 12. Linear Regression and Correlation. Introduction. The Fitted Regression Line. Parametric Interpretation of Regression: The Linear Model. Statistical Inference Concerning B1. The Correlation Coefficient. Guidelines for Interpreting Regression and Correlation. Perspective. Summary of Formulas. 13. A Summary of Inference Methods. Introduction. Data Analysis Samples. Appendices. Chapter Notes. Statistical Tables. Answers to Selected Exercises. Index. Index of Examples.

Applications of inferential statistical methods in library and information science

Familial isolated hyperparathyroidism: clinical and genetic characteristics of 36 kindreds.

Background: Non-alcoholic fatty liver disease (NAFLD) has an increasing trend in the world and can lead to liver failure and death if left untreated. Lifestyle modification is very important in the treatment of this disease. Objectives: This study aimed to determine the comparison of body mass index (BMI), smoking, vitamin E consumption, and type of oil consumed by patients with NAFLD with non-alcoholic patients. Methods: The present study was a retrospective case-control study that was performed on 120 patients referred to the ultrasound unit of Shohaday Ashayer Hospital in Khorramabad. The participants were divided into two groups, including case (61 people) and control (59 people). The questionnaire consisted of three parts: (1) the first part was related to demographic information; (2) the second part was related to liver ultrasound results; (3) and the third part was related to height, weight, BMI, weekly vitamin E intake, daily smoking status, and type of oil consumed. Data were analyzed using SPSS-23 software and descriptive and inferential statistical methods. Results: Most of the participants in the study were 69 (55.8%) and 92 (76.66%) were married. The mean BMI of patients with NAFLD was significantly higher than non-alcoholic patients (P = 0.003). There was no statistically significant difference in daily smoking and weekly intake of vitamin E in patients with and without non-alcoholic fatty liver disease (P &lt; 0.05). According to Fisher's exact test, it was found that there was a statistically significant difference in the frequency by patients with NAFLD and non-alcoholic (P = 0.014). Also, a statistically significant difference was observed in the frequency of the type of oil consumed by patients with NAFLD (P = 0.014). Conclusions: Consumption of olive and sesame oil along with weight loss is recommended. Smoking as a risk factor, as well as the use of vitamin E to prevent and treat NAFLD, require further studies with a larger sample size.

Long Pentaxin 3 is highly expressed by non-hematopoietic cells during Streptococcus pneumoniae invasive infections and regulates polymorphonuclear neutrophils' recruitment through interaction with P-selectin which damps inflammation-associated tissue damage and pneumococcal systemic dissemination.

A Novel PD-L1-targeting Antagonistic DNA Aptamer With Antitumor Effects.

Study of genes and environmental factors in complex diseases

The misuse of statistical methods in diagnostic accuracy studies has been criticized in many publications. To assess the use and misuse of statistical methods in medical journal articles. We reviewed 141 original articles from 6 cytopathology journals published in 2014. In total, 16 articles used no descriptive statistics and 66 articles used no inferential statistics. Also, 82 articles did not report using any tests for diagnostic accuracy. The most commonly adopted statistical measure for diagnostic accuracy was sensitivity, followed by specificity. The most common inferential statistical methods were χ2 testing, the Fisher exact test, and the Cohen kappa coefficient, respectively. Only 78 articles were free of statistical errors. "No statistics were used although statistical methods were required" was the most common type of error, followed by "failure to select proper statistical methods." Our assessment of use of statistical methods in this subsection of pathology demonstrated a need for improvement.

In this study, we analyzed the impact of occupational/household chronic exposure to pesticides on the clinicopathological profile of breast cancer in rural women from Paraná southwest, a predominantly rural landscape with large pesticide uses. A total of 349 women were included in the study. After a structured interview, women were categorized as exposed (n = 208) or unexposed (n = 141) to pesticides. Clinicopathological data were collected from medical records. Descriptive and inferential statistical methods were used to characterize and compare the sample. The Chi-square test and Fisher's exact test were used to evaluate differences between the molecular subtypes and clinicopathological variables of patients. Exposed patients had a prevalence of the Luminal B subtype (32.83%), while unexposed patients had a prevalence of the Luminal A molecular subtype (37.78%, p <= 0.05). Exposed patients also had higher disease recurrence (10.19%), chemoresistance (21.26%), than unexposed patients (p <= 0.05). Breast cancer patients exposed to pesticides were also more likely to have distant metastases (1.4 times) and lymph node invasion (1.3 times) compared to patients not exposed. These findings indicate that pesticide exposure favors the occurrence of more aggressive breast cancer.

This study aimed to assess the effect of yoga on overall anxiety, of pregnant women trait and state. The population of 350 pregnant women attending prenatal care clinics in Yazd city. To conduct this study (50) pregnant women were randomly assigned to two experimental groups (n = 25) and testifier group (n = 25) were replaced. To collect the data of Eshpilberger anxiety questionnaire executed at first. Then the special program yoga, every 2 months, 2 weeks Session 1.5 hour tests were conducted on groups. To test hypotheses and analyze data, descriptive and inferential statistical methods are used. In descriptive statistics, graphs, mean and standard deviation and in part of inferential statistics to examine the first hypothesis, analysis of covariance and multivariate covariance analysis is used to examine two hypotheses. The results show that multivariate variance in the post test of experimental group, show meaningful differences from anxiety variables in level of p < 0.005. In other words Yoga interventions lead to significant reduction in experimental group. So yoga is effect on reducing overall state and trait anxiety.

The majority of pregnancy loss in cattle occurs during the first 2 to 3 weeks of pregnancy. This loss can be studied by the transfer of in vivo- and in vitro-produced embryos. The objective of this study was to examine the relationship between recipient serum progesterone levels both at the time of embryo transfer and at conceptus recovery on conceptus development from in vivo- or in vitro-produced embryos. Embryos were produced in vivo by superovulation of Holstein cows (IVO; n = 17) or in vitro with either serum-containing (IVPS; n = 27) or serum-restricted medium (IVPSR; n = 34). Single grade-1 blastocysts from each embryo production system were transferred into heifers at Day 7. Conceptuses were recovered at Day 17 of gestation (number recovered/number transferred: IVO, 11/17; IVPS, 16/27; IVPSR, 18/34) and classified as complete, degenerated, or no conceptus. Recipient serum progesterone concentrations were determined by radioimmunoassay and compared with conceptus development outcomes. Sex of conceptus was determined by PCR using a Y-chromosome specific probe. Data were analysed using Fisher's exact test or ANOVA and Duncan's multiple range test. Compared with the IVO group, in vitro-produced embryos had more (P = 0.055) degenerated conceptuses (IVO, 0%; IVPS, 18.5%; IVPSR, 20.6%). There were no differences (P &gt; 0.05) in serum progesterone concentrations in recipients assigned to different treatments at Day 7. There was also no effect (P &gt; 0.05) of treatment on progesterone levels in recipients with either male or female conceptuses at the time of transfer. Interestingly, heifers in the in vitro treatment groups had lower (P &lt; 0.01) progesterone concentrations at Day 7 when no conceptus was recovered at Day 17 (IVPS, 2.1 ± 0.4 ng mL–1; IVPSR, 2.7 ± 0.4 ng mL–1; Least squares means ± standard error of the mean) compared with the IVO group (4.5 ± 0.6 ng mL–1). There was no difference in progesterone concentration between treatment groups for heifers with shorter conceptuses (≤194 mm). However, when longer (&gt;194 mm) conceptuses were recovered, heifers with in vitro produced embryos had lower (P &lt; 0.05) progesterone levels at Day 7 compared with those with in vivo produced embryos (IVPS, 2.2 ± 0.6 ng mL–1; IVPSR, 2.3 ± 0.5 ng mL–1; IVO, 3.9 ± 0.6 ng mL–1). In summary, serum progesterone concentrations in recipients at the time of transfer of in vivo- or in vitro-produced embryos were associated with conceptus development at Day 17 of gestation. Research supported by NC State University GAANN Biotechnology Fellowship (C. V. Barnwell) and the College of Veterinary Medicine.