Comparing Two Sample Means t Tests

Witt, Philip L.; McGrain, Peter

doi:10.1093/ptj/65.11.1730

Cited by 11 publications

(11 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“… *Estimates are reported as mean (SD) for continuous variables; and N (%) for categorical variables. †Differences in means were tested using Student’s t-test) 54 ; dependence between categorical variables was tested using Pearson’s χ 2 test 55 . …”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Adverse childhood experiences (ACEs) and later-life depression: perceived social support as a potential protective factor

et al. 2017

View full text Add to dashboard Cite

ObjectiveTo investigate associations between adverse childhood experiences (ACEs) and later-life depressive symptoms; and to explore whether perceived social support (PSS) moderates these.MethodWe analysed baseline data from the Mitchelstown (Ireland) 2010–2011 cohort of 2047 men and women aged 50–69 years. Self-reported measures included ACEs (Centre for Disease Control ACE questionnaire), PSS (Oslo Social Support Scale) and depressive symptoms (CES-D). The primary exposure was self-report of at least one ACE. We also investigated the effects of ACE exposure by ACE scores and ACE subtypes abuse, neglect and household dysfunction. Associations between each of these exposures and depressive symptoms were estimated using logistic regression, adjusted for socio-demographic factors. We tested whether the estimated associations varied across levels of PSS (poor, moderate and strong).Results23.7% of participants reported at least one ACE (95% CI 21.9% to 25.6%). ACE exposures (overall, subtype or ACE scores) were associated with a higher odds of depressive symptoms, but only among individuals with poor PSS. Exposure to any ACE (vs none) was associated with almost three times the odds of depressive symptoms (adjusted OR 2.85; 95% CI 1.64 to 4.95) among individuals reporting poor PSS, while among those reporting moderate and strong PSS, the adjusted ORs were 2.21 (95% CI 1.52 to 3.22) and 1.39 (95% CI 0.85 to 2.29), respectively. This pattern of results was similar when exposures were based on ACE subtype and ACE scores, though the interaction was clearly strongest among those reporting abuse.ConclusionsACEs are common among older adults in Ireland and are associated with higher odds of later-life depressive symptoms, particularly among those with poor PSS. Interventions that enhance social support, or possibly perceptions of social support, may help reduce the burden of depression in older populations with ACE exposure, particularly in those reporting abuse.

show abstract

Section: Resultsmentioning

confidence: 99%

“… †Differences in means were tested using Student’s t-test) 54 ; dependence between categorical variables was tested using Pearson’s χ 2 test 55 . …”

Section: Resultsmentioning

confidence: 99%

Adverse childhood experiences (ACEs) and later-life depression: perceived social support as a potential protective factor

et al. 2017

View full text Add to dashboard Cite

show abstract

“…Groups 1 and 2 were combined as an experimental group by averaging the chemotaxis index of group 1 and the reciprocal of the chemotaxis index of group 2. Three replicates were performed, and a probability of P Ͻ 0.05 was considered statistically significant (23 ). All computations were made using SPSS software (SPSS Inc.).…”

Section: Data Collection and Statisticsmentioning

confidence: 99%

Integration of Sperm Motility and Chemotaxis Screening with a Microchannel-Based Device

et al. 2010

View full text Add to dashboard Cite

BACKGROUND Sperm screening is an essential step in in vitro fertilization (IVF) procedures. The swim-up method, an assay for sperm motility, is used clinically to select the ideal sperm for subsequent manipulation. However, additional parameters, including acrosome reaction capability, chemotaxis, and thermotaxis, are also important indicators of mammalian sperm health. To monitor both sperm motility and chemotaxis simultaneously during sperm screening, we designed and constructed a microdevice comprising a straight channel connected with a bibranch channel that mimics the mammalian female reproductive tract. METHODS The width and length of the straight channel were optimized to select the motile sperms. We selectively cultured cumulus cells in the bibranch channel to generate a chemoattractant-forming chemical gradient. Sperm chemotaxis was represented by the ratio of the sperm swimming toward different branches. RESULTS The percentage of motile sperms improved from 58.5% (3.8%) to 82.6% (2.9%) by a straight channel 7 mm in length and 1 mm in width. About 10% of sperms were found to be chemotactically responsive in our experiment, which is consistent with previous studies. CONCLUSIONS For the first time, we achieved the combined evaluation of both sperm motility and chemotaxis. The motile and chemotactically responsive sperms can easily be enriched on a lab-on-a-chip device to improve IVF outcome.

show abstract

“…The porosity fraction was quantified to be 0.03 ± 0.01% and 0.05 ± 0.01% of the representative volume for PSG and NPSG, respectively. By performing a t -test [ 40 ], it was found that the two porosity distributions can be assumed to be statistically different, leading to a conclusion that the pre-stress increased the compactness of the powder of which the gears were composed. The t -test was conducted at the 95% confidence level and took into account the measurement uncertainty of the porosity fractions.…”

Section: Resultsmentioning

confidence: 99%

“…The dimensional analysis of the gears was based on the actual-to-nominal comparison tool [ 40 ]. The use of the actual-to-nominal comparison allows the quantification of the deviation of each surface point of an object compared to its CAD file [ 36 ].…”

Section: Resultsmentioning

confidence: 99%

Designing a Tool System for Lowering Friction during the Ejection of In-Die Sintered Micro Gears

2017

View full text Add to dashboard Cite

The continuous improvements in micro-forging technologies generally involve process, material, and tool design. The field assisted sintering technique (FAST) is a process that makes possible the manufacture of near-net-shape components in a closed-die setup. However, the final part quality is affected by the influence of friction during the ejection phase, caused by radial expansion of the compacted and sintered powder. This paper presents the development of a pre-stressed tool system for the manufacture of micro gears made of aluminum. By using the hot isostatic pressing (HIP) sintering process and different combinations of process parameters, the designed tool system was compared to a similar tool system designed without a pre-stressing strategy. The comparison between the two tool systems was based on the ejection force and part fidelity. The ejection force was measured during the tests, while the part fidelity was documented using an optical microscope and computed tomography in order to obtain a multi-scale characterization. The results showed that the use of pre-stress reduced the porosity in the gear by 40% and improved the dimensional fidelity by more than 75% compared to gears produced without pre-stress.

show abstract

Comparing Two Sample Means t Tests

Cited by 11 publications

References 1 publication

Adverse childhood experiences (ACEs) and later-life depression: perceived social support as a potential protective factor

Adverse childhood experiences (ACEs) and later-life depression: perceived social support as a potential protective factor

Integration of Sperm Motility and Chemotaxis Screening with a Microchannel-Based Device

Designing a Tool System for Lowering Friction during the Ejection of In-Die Sintered Micro Gears

Contact Info

Product

Resources

About