If the variances of two treatment groups are heterogeneous and, at the same time, sample sizes are unequal, the Type I error probabilities of the pooledvariances Student t test are modified extensively. It is known that the separate-variances tests introduced by Welch and others overcome this problem in many cases and restore the probability to the nominal significance level. In practice, howev...

109 retrieved after testing and subjected to threepoint bending (Figure 1B) and pull-out tests (Figure 1C) to elucidate differences in relevant performance characteristics. One-tailed paired student’s t-tests were used to evaluate the injuries applied to the specimens. For all other tests in this study, two-tailed, two-sample, equal variance t-tests were used with significance levels set at p=0...

A number of recent studies have demonstrated that the microvolt level T wave alternans measured during bicycle exercise can identify patients at high risk for developing malignant ventricular arrhythmias. However, little is known about the reproducibility of T wave alternans measured during bicycle exercise. The purpose of this study was to prospectively evaluate the immediate reproducibility o...

Immunoglobulin secretion was studied in 37 patients between 19 and 106 days after allogeneic HLA-identical (30 patients), allogeneic one HLA-haplotype-identical (three patients), syngeneic (three patients), or autologous (one patient) marrow grafting. E rosette-positive (T) and E rosette-negative (non-T) peripheral blood mononuclear cells were cocultured with pokeweed mitogen for 6 days. Polyva...

We continue our study of significance tests. In these notes we will introduce two new tests: one-sample t-tests and two-sample t-tests. You should pay careful attention to the fact that every test makes some assumptions about the data – often that is drawn from a normal distribution. You should also notice that all the tests follow the same pattern. It is just the computation of the test statis...

We continue our study of significance tests. In these notes we will introduce two new tests: one-sample t-tests and two-sample t-tests. You should pay careful attention to the fact that every test makes some assumptions about the data – often that is drawn from a normal distribution. You should also notice that all the tests follow the same pattern. It is just the computation of the test statis...

The blood lymphocytes from a case of prolymphocytic leukaemia were subjected to a battery of different tests in order to establish as certainly as possible their T or B cell type of origin. The results of the tests for surface markers indicated the T-cell origin of the leukaemic cells in this patient, and this provided a good opportunity to determine the participation of T cells in the various ...

PURPOSE The purpose of this study was to compare the results of commercial chairside microbial tests (CT) and conventional selective media (GS, gold standards) for mutans streptococci (MS) and lactobacilli (LB) using oral specimens from young children with and without visible dental caries. METHODS Using cotton swabs to collect oral microbial specimens from children 10 to 36 months old, micro...

Modern real-time systems have to be adaptable and flexible to deal with non-periodic events, requiring a means of checking for schedulability during execution time. Thus, online schedulability tests are a fundamental building block in the design of such systems. Usually, when such tests are carried out at time t they either consider or not future events that occur after t. Those that take such ...