Spss statistics for windows v 21

Measurement data will be expressed as the means ± standard deviations, and count data will be expressed as frequencies. Data will be analysed using SPSS Statistics for Windows v21 (IBM, Armonk, NY, USA). Pearson’s χ2 test or Fisher’s exact test will be used to analyse classified variables. The t test will be used if the normal distribution and homogeneity test are satisfied, and the rank sum test will be used for nonnormality or nonuniformity of variance. The Kruskal‒Wallis test will be used for multigroup comparisons, and the Wilcoxon rank sum test will be used for comparisons between two samples. For repeated measurement data, repeated measurement analysis of variance will be used. For the pairwise comparison of multiple groups of data, the Bonferroni method will be used to adjust the test level.

Descriptive statistics were calculated (e.g., median, mean, and standard deviation). Spearman's correlation coefficient was used to measure the association between variables because the data did not follow a normal distribution. Furthermore, regression analysis was employed to determine the factors that had significant effects on MHL. Factor analysis was performed on the 35 items of MHLS—Arabic version. Significant findings were inferred if p < 0.05. The data were processed using IBM SPSS Statistics for Windows v.21 (Armonk, New York: IBM Corp. 2012).

Data analysis was performed using IBM SPSS Statistics^® for Windows, v.21 and strengths and weaknesses were collected on a report following the criteria scheme proposed by AHRQ. Thus, for the descriptive analysis of sociodemographic characteristics and PS items and dimensions, frequencies and percentages were calculated. Pearson’s chi-square test was used to compare variables between two or more groups. A 95% confidence interval was used. In addition, a reliability test of the dimensions was carried out by calculating Cronbach’s alpha and analyzing the negative responses in a Pareto diagram.

Chi-square test was used for comparisons of rates (autogeny, stenogamy and the molecular forms of Cx. p. pipiens), Kruskal-Wallis H test to study the spatial variation of rates (autogeny, stenogamy) and Mann-Whitney test to evaluate the influence of blood meal on fecundity and fertility rates. All statistical tests were conducted using the IBM® SPSS® Statistics for windows v.21 (IBM Corp. Armonk, NY). P-values > 0.05 were considered non-significant.

Data from qPCR were processed in IBM SPSS Statistics for Windows v21 (IBM Corp., Armonk, NY) using the Mann–Whitney U-test to compare the concentrations of bacteria in the two diet groups. Fisher’s exact test was performed to determine if there was an association between diet group and low (<1,000 pg DNA/µL) or high (≥1,000 pg DNA/µL) concentrations of S. wiggsiae. Data from HOMINGS were processed by MeV v4.9 [19 (link)] and GraphPad Prism (GraphPad Software, Inc., La Jolla, CA) to calculate the Shannon diversity index (α-diversity). Data reduction and graphic presentation using principal component analysis and correspondence analysis were performed. Comparisons of the two diet groups at probe level were made using the Mann–Whitney U-test. An adjusted p-value of <0.05 was considered significant. Demographics of subjects with and without sufficient DNA in plaque samples were compared by Student’s t-test (age, sex, DMFT) and Mann–Whitney U-test (oral hygiene).
Sample size was based on results from a previous study analyzed with the same assays [20 (link),21]. It was estimated that approximately 30 subjects in each sugar category would be sufficient in order to avoid type I and type II errors.