Báo cáo y học: "Statistics review 14: Logistic regression" doc
Báo cáo y học: "Statistics review 14: Logistic regression" doc
... binary (e.g. death or survival),
then the probability distribution of the number of deaths in a
sample of a particular size, for given values of the explanatory
Review
Statistics review 14: Logistic ... the
explanatory variables is assessed by carrying out statistical
tests of the significance of the coefficients. The overall
goodness of fit of the model is then tested. Additionally,...
Báo cáo y học: " Statistics review 6: Nonparametric methods" docx
... than some hypothesized value,
and considers whether this is substantially different from what
we would expect by chance. If any observations are exactly
equal to the hypothesized value they are ignored ... be
Normally distributed, whereas the sign test only requires that
they are independent of one another. Alternatively, the dis-
crepancy may be a result of the difference in power provided
b...
Báo cáo y học: " Statistics review 11: Assessing risk" doc
... viable in this type of
study, but RR is generally easier to interpret.
The AR indicates that 14.4% of the successful outcomes can
be directly attributed to the early goal-directed therapy and is
calculated ... prospective
cohort study conducted by Quasney and coworkers [1] of
402 adults admitted to the Memphis Methodist Healthcare
System with community-acquired pneumonia. That study
investiga...
Báo cáo y học: "Statistics review 1: Presenting and summarising data" pptx
... plots
Unordered Ordered
Discrete
Continuous
Ventilatory support
Severity of illness
Days in ICU Blood pressure
Main types:
In tables, shown as:
Graphically shown as:
Types:
Examples:
Table 1
Haemoglobin (g/dl) ... median,
the interquartile range is not influenced by unusually high or
low values and may be particularly useful when data are not
symmetrically distributed. Ranges based on alterna...
Báo cáo y học: "Statistics review 2: Samples and populations" potx
... approximately Normal and that the popula-
tion SD can be approximated by the sample SD. These
assumptions, particularly the first, will generally be valid if the
sample is sufficiently large. There may ... distribution is extremely non-Normal and the
sample size is very small then it may be necessary to use non-
parametric methods. (These will be discussed in a subse-
quent review. ) However...
Báo cáo y học: "Statistics review 4: Sample size calculations" doc
... sufficiently small P value. Similarly, a
study with high statistical power will, by definition, make iden-
tification of any difference relatively easy, but this can only be
achieved in a sufficiently ... apparently null
result that shows no difference between groups may simply
be due to lack of statistical power, making it extremely unlikely
that a true difference will be correctly identifie...
Báo cáo y học: "Statistics review 5: Comparison of means" docx
... subsequent treatment
may increase central venous oxygen saturation beyond the
level expected by chance.
However, the P value in isolation gives no information about
the likely size of any effect. As indicated ... early goal-directed therapy may be successful in raising
mean arterial pressure by between 9.3 and 18.7 mmHg. As
always, it is important to interpret this finding in the context of
t...
Báo cáo y học: " Statistics review 12: Survival analysis" ppt
... age > 65 years or
≤ 65 years, and (b) long-term oxygen therapy (LTOT) before intensive
care unit admission (yes/no). The P values are for the log rank test.
391
test the null hypothesis that ... bronchiectasis
Explanatory 95% confidence
variables Risk ratio interval P
Age (>65 years) 2.7 1.15–6.29 0.022
LTOT (yes) 3.12 1.47–6.90 0.003
LTOT, long-term oxygen therapy.
... time, the
star...