The more statistical tests we perform, the more likely we are to reject the null hypothesis when it is true (i.e., a “false alarm,” also called a “Type 1” error). This is a consequence of the logic of hypothesis testing: We reject the null hypothesis for rare events, and the larger the number of tests, the easier it is to find rare events which are false alarms. This problem is called the infla...

a total of 711 beta-hemolytic streptococci were isolated from throat cultures of patients during 1970-73. these strains were grouped in parallel by the precipitin and bacitracin paper disk method. the former method was estab­lished as the standard by which the bacitracin technique was compared. the difference in results was about 5.67%. the greatest error (5.4%) was seen with non-group a strain...

BACKGROUND Fear of falling (FOF) is commonly experienced in people with Parkinson's disease (PD). It is a predictor of recurrent falls, a barrier to physical exercise, and negatively associated with health-related quality of life. A variety of rating scales exist that assess different aspects of FOF but comprehensive head-to-head comparisons of their psychometric properties in people with PD ar...

Three different potential predictors of forecast error – ensemble spread, mean errors of recent forecasts and the local gradient of the predicted field – were compared. The comparison was performed using the forecasts of 500 hPa geopotential and 2-m temperature of the ECMWF ensemble prediction system at lead times of 96, 168 and 240 h, over North America for each day in 2004. Ensemble spread wa...

In this paper a method of embedding a linear graph in n-cube is discussed. Necessary and sufficient conditions on node configurations for the embeddability are obtained by analyzing the structure of n-cube in code space with respect to the distance 2c by means of Reed-Muller code. The fundamental idea in this study is to modify a given graph iteratively in such a manner that the connecting prop...

Consider the problem of testing s hypotheses simultaneously. The usual approach to dealing with the multiplicity problem is to restrict attention to procedures that control the probability of even one false rejection, the familiar familywise error rate (FWER). In many applications, particularly if s is large, one might be willing to tolerate more than one false rejection if the number of such c...

1 Abstract Two types of errors can be associated with classifying data into two categories A and B: misclassifying an item in A as one of B and, conversely, misclassifying an item in B as one of A. Tight control over these two errors is needed in many practical situations. For example, an error of one type may have far more serious consequences than one of the other type. Most previous work on ...

BACKGROUND Freshman experiences can greatly influence students' success. Traditional methods of monitoring the freshman experience, such as conducting surveys, can be resource intensive and time consuming. Social media, such as Twitter, enable users to share their daily experiences. Thus, it may be possible to use Twitter to monitor students' postsecondary experience. OBJECTIVE Our objectives...

Fisher's exact test for comparing response proportions in a randomized experiment can be overly conservative when the group sizes are small or when the response proportions are close to zero or one. This is primarily because the null distribution of the test statistic becomes too discrete, a partial consequence of the inference being conditional on the total number of responders. Accordingly, e...

In the United States the preferred method of obtaining dietary intake data is the 24-hour dietary recall, yet the measure of most interest is usual or long-term average daily intake, which is impossible to measure. Thus, usual dietary intake is assessed with considerable measurement error. We were interested in estimating the population distribution of the Healthy Eating Index-2005 (HEI-2005), ...