Effect of Correlations on Type 1 Error Rates of Some Multivariate Normality Tests

Normality assumption of multivariate data is a prerequisite to the use of multivariate statistical data analysis methods before inference could be valid and reliable. Tests developed to validate this assumption including Doornik-Harsen (DH), Shapiro-Francia (SF), Mardia Skewness (MS), Mardia Skewness for small sample (MSS) and Kurtosis (MK), Skewness (S) and Kurtosis(K), Shapiro-Wilk(SW), Royston (R), Desgagne-Micheaux (DM), Henze-Zirkler (HZ), Energy (E), Gel-Gastwirth (GG) and Bontemps-Meddahi (BM) tests often result into different conclusions. These differences can be misleading. Consequently, this paper examined the effect of correlations on the Type 1 error rates of multivariate tests of normality. Monte Carlo experiments were conducted one thousand (1000) times taking into consideration the dimensions, correlations and sample sizes of the multivariate data. A test is affected by correlation if its estimated Type 1 error rate changes as correlation changes. A test is considered good if its estimated error rate approximates the true error rate and best if the number of times it approximates the estimated error rate when counted over the levels of correlations, sample sizes and levels of significance is the highest, the mode. Results show that Type 1 error rates of DH, SF, SW, R, DM, GG and BM tests are affected by correlations and are relatively not good; where as the Type 1 error rates of HZ, MS, MK, MSS, S, K and E tests are not only unaffected by correlations but are also relatively good. Consequently, MS, R, MSS, HZ and E tests have good Type 1 error rates but that of E and HZ tests are best. They are therefore recommended for practitioners

In–Vitro Antibacterial and Antifungal Efficacy of Greenly Fabricated Senna alata Leaf Extract Silver Nanoparticles and Silver Nanoparticle-Cream Blend

Nanoparticles biosynthesis has been extensively studied for its biomedical applications. In this study, the in-vitro antibacterial and antifungal activity of greenly fabricated silver nanoparticles (NPs) from Senna alata leaf extract (SaAgNPs) and silver nanoparticle cream blend (SaAgNPs-cream blend) were investigated. The SaAgNPs were characterized using UV-visible spectrophotometry, FTIR, SEM, TGA, DLS, EDX, and XRD. The presence of surface plasmon band around 500 nm indicates AgNPs formation and functional groups such as alkenes, carboxylic acids, and alkyl aryl ether responsible for capping and stabilization of the nanoparticles. The SaAgNPs were spherical and 1.00 µm in size; TGA shows the formation of stable SaAgNPs, DLS shows 1.8 % intensity with 1905 nm average diameter and a polydispersity index of 0.595. EDX analysis confirmed the formation of pure silver nanoparticles. SaAgNPs supported the production of cosmetically acceptable SaAgNPs-cream blend with appropriate pH and viscosity. SaAgNPs and the SaAgNPs cream-blends had antibacterial activity against all and some of the test bacterial and fungal isolates. SaAgNPs had the highest activity against Pseudomonas aeruginosa 27853, Rhizopus sp. and Candida tropicalis with a zone of 16 mm and 30 mm. The cream-blends had activity against 68.75 % and 75 % of the test bacteria and fungi with the highest activity against Streptococcus epidermidis B (7.0 mm) and Candida albicans B (8.0 mm). In conclusion, the crude Senna alata leaf extracts, the bio-fabrication SaAgNPs and SaAgNPs-cream blend have antibacterial antifungal potentials which can be effectively utilized for the control of pathogenic bacteria and fungi

A Comparative Study Of Probioticated Kunun-Zaki By Probiotic Strains Of Pediococci spp. And Lactobacillus rhamnosus GG

Non-dairy probiotic functional foods are receiving considerable interest recently owing to the inability to cause allergy in certain segments of the population. Studies on probiotication were carried out to determine the suitability of kunun-zaki as food matrix for production of probiotic beverage using single and mixed culture of Pediococcus acidilactici KU7, Pediococcus pentosaceus CREC5 and Lactobacillus rhamnosus GG. Probioticated and un-probioticated kunun-zaki samples were designated PKZ and UPKZ, respectively. There was a significant difference in the viable count during storage. Viable counts of the LAB strains decreased with increasing storage time with P. acidilactici KU7 having the highest viability at the beginning and end of storage (3.43 ± 0.06 and 0.93± 0.12 x108 cfu/ml). There was a decrease in pH of the PKZ samples within the 1st and 3rd week with corresponding increase in lactic acid production (71.16 ± 0.01 – 441.39 ± 0.01). Marked increase in pH and a decline in lactic acid were observed at the 4th week of storage in all samples. Total soluble solids content of the beverage was observed to decrease with increasing storage time ranging from 8.25 ± 0.01-4.97± 0.01. There was no significant difference in pH and total soluble solids of UPKZ and colour of the PKZ and UPKZ samples during storage. All the PKZ samples were able to inhibit the growth of selected pathogens with marked variability amongst the samples. The UPKZ sample also showed slight inhibitory activity. The samples showed a decline in proximate and mineral composition at the end of storage. Sensory evaluation showed the PKZ samples were preferred over the UPKZ samples. This study shows that probioticated kunun-zaki can serve as a suitable non-dairy alternative to dairy probiotic formulations and would be of health benefits to potential consumers