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345 protocols using stata se 13

1

Statistical Analysis of Acetyllysine Distributions

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Calculations of differences between actual versus expected lysine frequency were performed utilizing a comparison of proportions and applying a Bonferroni correction to P values for multiple comparisons (108 ) using Microsoft Excel 2010. The test of independence comparing log- and stat-phase acetyllysine distributions was performed similarly. All subsequent statistical analyses were performed using Stata/SE 13.1. While the utilization of Pearson’s correlation coefficient is more common when analyzing the correlation between variables, we wanted to look at a more general association between lysine number or protein abundance and number of acetylation sites. For this reason we used a Spearman rank correlation, since it is not limited to simple linear relationships and is also nonparametric (109 (link)). The distributional dot plots were constructed using Stata/SE 13.1. Differences between mean width and length were analyzed using a one-way analysis of variance (ANOVA) followed by post hoc t test. All P values displayed have been Bonferroni corrected to account for multiple comparisons.
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2

Assessing State Law Impact on District Policy

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Using svy commands in Stata/SE 13.1 accounting for sampling strata and the weights described above (with scaling to account for strata with a single sampling unit), descriptive statistics were computed for the mean prevalence of items addressed within each domain and across all domains and all districts. The state law data represent a census of the 20 states' data and, therefore, were unweighted.
To assess the extent to which state law predicted district policy attention to the various domains and overall, unadjusted and adjusted linear regressions were computed using svy commands in Stata/SE 13.1. The unadjusted models included the state summary score for each domain (or overall) as the predictor and the district policy summary score for each domain (or overall) as the outcome. The adjusted models added in controls for majority race/ethnicity of the districts' students, FRPL eligibility, urbanicity/locale, district size, and Census region. Finally, Appendix S2 models 2 scenarios: the predicted change in district policy scores by domain and overall if (1) the state law score was at the mean for the given domain or overall, and (2) if the state law fully covered the domain or all 79 items examined for this study.
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3

Mortality Prediction in Aging Populations

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Mean number of hospital days (within 1, 3 and 10 years from baseline visit) and 95% confidence intervals were calculated, by age group and MPI level, and quantitative tests for trend were performed across levels of MPI within each age group. Median time to death for medium and high MPI risk groups and 95% confidence intervals were calculated, in comparison to the MPI low risk group using Laplace regression [31 (link)], in three separate sets of models: unadjusted, adjusted only for age, and adjusted for age and gender. All analyses were stratified by four age groups: sexagenarians (age cohort 66), septuagenarians (age cohorts 72 and 78), octogenarians (age cohorts 81, 84 and 87) and nonagenarians (age cohorts 90, 93, 96, 99). This age stratification was necessary because as expected, both MPI and number of hospital days and time to death were highly correlated with age. However, the Laplace regression mortality analyses excluded sexagenarians as too few of this age group had died by the censoring date for mortality. Statistical analyses were performed with STATA/SE 13.1 software (Texas, USA). Statistical significance was based on p-values <0.05.
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4

Breast Cancer Recurrence Risk Analysis

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The interquartile range was calculated for each SNP and the 20 most varied were selected and analyzed separately. For each SNP, the patients were divided into two groups based on their gene copy number, with the median value as a cut-off. To compare the association between RAB6C and clinical characteristics, the Pearson χ2 test was utilized.
Cumulative distant-recurrence risk was estimated using the Kaplan-Meier method. In the public data set, distant recurrence was calculated as previously described by Zhang et al (3 (link)). In the independent cohort, the end-point was defined as the first distant recurrence from the patient's primary breast tumor as described by Rutqvist and Johansson (15 (link),16 (link)). In this cohort, 3 patients died from breast cancer, but no date of distant recurrence was recorded. For these patients, the date of death was used as date of distant recurrence. Patients were censored at the last follow-up or at death due to causes other than breast cancer. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox's proportional hazards model. P-values were obtained from two-sided Wald tests and the patients were followed up until 10 years after diagnosis. The microarray data was processed using R 2.14.1 and the statistical analyses were performed with Stata/SE 13.1 software.
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5

AA Patient Satisfaction and Unmet Needs

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Data from the AA Patient Satisfaction and Unmet Need Survey are presented overall for the 11 countries. In addition, participants were stratified according to sex (female, male), current age (≤40 years, 41–50 years, >50 years), duration of AA since diagnosis (<2 years, 2–4 years, >4 years), and current severity of scalp hair loss (<50%, 50–94%, ≥95%).
Data were analyzed descriptively. Continuous variables were described using mean and standard deviation (SD). Categorical variables were reported as the frequency and percentage within each category. No imputation of missing data was conducted. Analyses were performed using STATA/SE 13.1 software (StataCorp, College Station, TX 77845, USA).
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6

Smoking and Glaucoma Incidence

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Cox regression models were fit to assess the relationship between smoking status (never/former/current smoker) or cigarette pack-years and the incidence of glaucoma. Hazard ratios (HRs) and their 95% CI were calculated considering the never smoker status as the reference category. Participants contributed to the follow-up period up to the date of return of their last questionnaire, death, or diagnosis of glaucoma, whichever came first.
Potential confounders included as covariates in the multiple Cox models were age, sex, body mass index (kg/m2), omega 3: omega 6 ratio (quintiles), hypertension, type 2 diabetes, physical activity (tertiles), coffee consumption (4 categories), alcohol intake (quintiles), and adherence to the Mediterranean diet.
All P values presented are 2-tailed; P < 0.05 was considered a priori as statistically significant. All analyses were performed with STATA/SE 13.1 software (College Station, TX: StataCorp LP).
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7

Comparative Analysis of Survival Outcomes

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The demographic characteristics and adverse events of the individuals in the study were analyzed using the chi-square (χ2) test or rank-sum test. Kaplan–Meier estimates were used to compare PFS obtained from the log-rank test. ORRs were compared using the chi-square (χ2) test. The individual effects and interactions of various covariates on PFS were analyzed by Cox regression modeling. A two-tailed test with a p-value of <0.05 was regarded as statistically significant in all analyses. All statistical data were analyzed using Stata/SE 13.1 software (StataCorp LLC, College Station, TX, USA) to determine the baseline characteristics, treatment effectiveness, and safety.
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8

Meta-analysis of PFD and Inhaled NAC Effects

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The data extracted from the selected trials were used to generate forest plots in Stata SE 13.0 software (Stata Corp, College Station, TX, USA). The risk of patients experiencing side effects and other binary parameters are expressed as odds ratios (ORs) for both the included cohort and case-control studies. The changes in the PFT parameters and other continuous parameters are presented as standardized mean differences (SMDs) for different studies that adopted various PFT inclusion standards. We examined the level of heterogeneity to determine which type of analysis to use. If there was low heterogeneity (I2 less than 40%), then we used a fixed effects model. If the I2 statistic was greater than 40%, we applied a random effects model to summarize the data. Patients with the combination of PFD and inhaled NAC were only included in one case-control study [11 (link)], and the sensitivity analysis excluding the case-control study and the secondary analysis with only oral administration studies were completed in one step. Two-tailed p values less than 0.05 were considered significant.
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9

Prostate Cancer Biopsy Outcome Prediction

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Two types of biopsy outcome were tested in the study: PCa versus non-PCa and high-grade PCa versus everything else. The differences between the two types of biopsy outcome with respect to age, PV, tPSA, %fPSA, PSAD, p2PSA, %p2PSA, and PHI were assessed using the Student's t-test for normal data and the Wilcoxon rank sum test for skewed data. Due to nonnormal distributions of age, PV, tPSA, %fPSA, PSAD, p2PSA, %p2PSA, and PHI, these variables were log-transformed before any statistical analysis. The areas under the receiver operating characteristic (ROC) curves (AUC) of different variables (age, PV, tPSA, %fPSA, PSAD, p2PSA, %p2PSA, and PHI) were calculated in univariate regression analyses. AUC of PHI was compared separately with the AUC of age, tPSA, and %fPSA and multivariate analysis was used to assess the value of PHI in the diagnosis of PCa. The sensitivity and specificity of each variable were calculated to assess the diagnostic performance of the various assays in terms of PCa detection. All descriptive statistics and comparisons were performed using Stata/SE 13.0 software (StataCorp., College Station, TX, USA). A two-sided P < 0.05 was considered statistically significant in all of the analyses.
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10

Statistical Analysis of Medical Studies

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We used Stata/SE 13.0 software (StataCorp LP, College Station, TX, USA) and Review Manager, version 5.2.0 (Cochrane Collaboration, Oxford, UK) to perform data analysis. The I2 and χ2 tests were applied to assess heterogeneity. We considered I2 values of 25%, 50%, and 75% as low, medium, and high levels of heterogeneity, respectively. Random-effects models were used for studies with significant heterogeneity, and fixed-effects models were used for studies without significant heterogeneity. The mean difference (MD) was used to evaluate the continuous outcomes, and relative risk (RR) was used for dichotomous data. A p value <0.05 was taken to indicate statistical significance.
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