For pharmacometricians, probability theory is the very first obstacle towards the statistics since it is solely founded on mathematics. The purpose of this tutorial is to provide a simple version of introduction to a univariate random variable, its mean, variance, and the correlation coefficient of two random variables using as simple mathematics as possible. The definitions and theorems in this tutorial appear in most of the statistics books in common. Most examples are small and free of subjects like coins, dice, and binary signals so that the readers can intuitively understand them.
Mathematics ; Numismatics ; Probability Theory

OBJECTIVETo accomplish the computation of Fisher exact probability test for fourfold table data in Excel.

METHODThe computing program of exact probability method for medical data in fourfold table design was edited by employing the IF statement and the relevant functions, such as SUM, FACT, DSUM, etc in Excel. The computational results are compared and evaluated according to the case studies.

RESULTSThe output of Fisher Exact Probability was generated and presented correctly following the input of four numerical values into the computation program in the setting of Excel. The parametric outcomes are in agreement with those produced by SAS and SPSS, in the combination tables containing the P value, two-tailed cumulative P value, left-tailed P-value, right-tailed P-value, Chi2 values and P values both for direct Chi-squared test and corrected Chi-squared test.

CONCLUSIONSDirect Chi-squared test, corrected Chi-squared test combined with Fisher Exact Probability test for fourfold table data can be conveniently, rapidly, and accurately accomplished in Excel.

Confidence Intervals ; Probability ; Population

Conventional prediction model, as a static prediction model, can be only used to predict the probability of the occurrence of an event during the observation period using the information available at baseline survey. However, based on current clinical demands, dynamic prediction, which obtains prediction probabilities for both baseline survey and later time points given the history of the events and covariates up to that time, is gaining a growing attention. As a dynamic prediction model, the landmarking approach is simple, easy to use, computationally efficient and has a comparable performance of joint modeling, which makes it to be widely used in recent researches. Because of its limited application in China, this paper makes a brief introduction of its ideas and basic application to further promote its applications in clinical dynamic prediction.
China ; Humans ; Probability

OBJECTIVES: To calculate the likelihood ratios of incest cases using identity by descent (IBD) patterns. METHODS: The unique IBD pattern was formed by denoting the alleles from the members in a pedigree with a same digital. The probability of each IBD pattern was obtained by multiplying the prior probability by the frequency of non-IBD alleles. The pedigree likelihoods of incest cases under different hypotheses were obtained by summing all IBD pattern probabilities, and the likelihood ratio(LR) was calculated by comparing the likelihoods of different pedigrees. RESULTS: The IBD patterns and the formulae of calculating LR for father-daughter incest and brother-sister incest were obtained. CONCLUSIONS The calculations of LR for incest cases were illustrated based on IBD patterns.
Male ; Humans ; Incest ; Siblings ; Probability

This paper aims to construct a Bayesian(BN) fault diagnosis model of traditional Chinese medicine dry granulation based on the failure model and effect analysis(FMEA), effectively control risk factors and ensure the quality of granules.Firstly, the risk ana-lysis of dry granulation process was carried out with FMEA, and the selected medium and high risk factors were taken as node variables to establish corresponding BN network with causality.According to the mathematical reasoning method of probability theory, the model was accurately inferred and verified by Netica, and the granule nonconformance was used as the evidence for reversed reasoning to determine the most likely cause of the failure that affected the granule quality.The BN fault diagnosis model of traditional Chinese medicine dry gra-nulation was established based on the medium and high risk factors of process, prescription and equipment screened out by FMEA, such as roller pressure, raw material viscosity, clearance between rollers in the paper.The fault diagnosis of traditional Chinese medicine dry granulation process was then carried out according to the model, and the posterior probability of each node under the premise of nonconforming granule quality was obtained.This method could provide strong support for operators to quickly eliminate faults and make decisions, so as to improve the efficiency and accuracy for fault diagnosis and prediction, with innovation in its application.
Bayes Theorem ; Medicine, Chinese Traditional ; Probability

Twelve cases of histologically confirmed pituitary adenomas, classified as Grade 1 to 2B, underwent transsphenoidal surgery. Sixty-six percent of the tumors were functioning. Four of the tumors were microadenomas and 8 were macroadenomas, 5 of which had supresellar extensions. There was no operative mortality. The lone morbidity was that of a chronic subdural hematoma that was succesfully evacuated. The procedure provided a more rapid and direct access to the pituitary gland, better differentiation of the tumor from the gland, less trauma to the patient and less probability of injury to nearby structures. Visual function improvement and endocrinologic care rates were excellent.

OBJECTIVE: To explore the biomarkers of tinnitus in vestibular schwannoma patients using electroencephalographic (EEG) microstate technology. METHODS: The EEG and clinical data of 41 patients with vestibular schwannoma were collected. All the patients were evaluated by SAS, SDS, THI and VAS scales. The EEG acquisition time was 10-15 min, and the EEG data were preprocessed and analyzed using MATLAB and EEGLAB software package. RESULTS: Of the 41 patients with vestibular schwannoma, 29 patients had tinnitus and 12 did not have tinnitus, and their clinical parameters were comparable. The average global explanation variances of the non-tinnitus and tinnitus groups were 78.8% and 80.1%, respectively. The results of EEG microstate analysis showed that compared with those without tinnitus, the patients with tinnitus had an increased frequency (P=0.033) and contribution (P=0.028) of microstate C. Correlation analysis showed that THI scale scores of the patients were negatively correlated with the duration of microstate A (R=-0.435, P=0.018) and positively with the frequencies of microstate B (R=0.456, P=0.013) and microstate C (R=0.412, P=0.026). Syntax analysis showed that the probability of transition from microstate C to microstate B increased significantly in vestibular schwannoma patients with tinnitus (P=0.031). CONCLUSION EEG microstate features differ significantly between vestibular schwannoma patients with and without tinnitus. This abnormality in patients with tinnitus may reflect the potential abnormality in the allocation of neural resources and the transition of brain functional activity.
Humans ; Neuroma, Acoustic/complications* ; Electroencephalography ; Patients ; Probability

This study presents some of the first statistical findings of the Severance Hospital discharge survey. The purpose of this study described in this report was twofold: 1) The underlying consideration was model building for the distribution of short-stay hospitalized patients; and 2) The immediate target was a better understanding of the impact of certain measurement probability discharged as cured present in the survey of medical records. In building up the duration-of-stay model, the conditional probabilities of discharge on a particular day were computed for the January-December, 1967 in order to obtain an appropriate theoretical distribution. The rise and fall of these conditional probabilities as duration of stay increased was characteristic of the log-normal distribution. Therefore, the log-normal distribution, ... was fitted to the available duratin-of-stay data. The parameters found for the distribution were estimated as mu=1.834 and delta=0.675 in 1967. As for measuring the probability of patient discharged as cured, life table model was adopted. Discharge as cured including improved patient and death including transferred to other hospital without improved are takan as the two attrition factors for decrement of a single population. The probabilities of being discharged as cured during the first week after hospitalization were found .as P0=0.41877 in 1967, P0=0.44113 in 1968 and P0=0.47387 in 1969. The average expectations of post discharge life were e0=2.048 weeks in 1967, e0=2.160 weeks in 1968 and e0=1.961 weeks in 1969. During the first fourteen days after hospitalization the probabilities as cured were 2P0=0.6814 in 1967, 2P0=0.7056 in 1968 and 2P0=0.7352 in 1969, which showed the rate has been steadly increased.
Hospitalization* ; Human ; Korea ; Length of Stay ; Medical Records ; Models, Theoretical ; Probability

The method for detecting the negative terms in Chinese electronic medical record (EMR) is useful in providing evidence for constructing concept index. In this respect, we adopted an improved method which combined maximum matching with mutual information in order to extract terms in EMRs. This method can overcome the influence of overlay ambiguity. In addition, for the determination of negative semantic, we also adopted an improved method which combined rule-based method with word co-occurrence. This new method can reduce the probability of appearance of false positive terms caused by punctuation input errors. The result showed that the negative predictive value is 7.85% higher than the rule-based method.
China ; Electronic Health Records ; Probability ; Semantics ; Terminology as Topic