Báo cáo y học: "Statistics review 3: Hypothesis testing and P values" pdf
Báo cáo y học: " tatistics review 3: Hypothesis testing and P values." pdf
... a population from a
representative sample. A common next step in data analysis
is calculation of P values, also known as hypothesis testing.
Hypothesis testing is generally used when some comparison
is ... reviews.
Keywords hypothesis testing, null hypothesis, P value
Available online http://ccforum.com/content/6/3/222
greater, just by chance if the null hypothesis is true. B...
Báo cáo y học: "Statistics review 1: Presenting and summarising data" pptx
... 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) from 48 intensive care patients
5.4 ... or
box and whisker plots.
Tables and graphs provide a convenient simple picture of a
set of data (dataset), but it is often necessary to further sum-
marize...
Báo cáo y học: "Statistics review 2: Samples and populations" potx
... 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 be occasions when
these assumptions break ... the
present review concentrates specifically on estimation of a
population mean.
Consider all possible samples of fixed size (n) drawn from a
population. Each of these samples has its own mean...
Báo cáo y học: "Statistics review 4: Sample size calculations" doc
... approximately 86 (43 per arm) and
116 (58 per arm) for P values of 0.05 and 0.01, respectively.
The nomogram provides a quick and easy method for deter-
mining sample size. An alternative approach ... the
statistical power of the study. Put simply, this is the probabil-
ity of correctly identifying a difference between the two
groups in the study sample when one genuinely exists in th...
Báo cáo y học: "Statistics review 5: Comparison of means" docx
... data’,
‘samples and populations’, ‘hypotheses testing and P
values’ and ‘sample size calculations’. Future topics to be
covered include comparison of proportions, simple
regression and analysis of survival ... recently published trial that compared early goal-directed
therapy with standard therapy in the treatment of severe
sepsis and septic shock [1]. A total of 263 patients we...
Báo cáo y học: " Statistics review 6: Nonparametric methods" docx
... ‘presenting and summarizing data’,
‘samples and populations’, ‘hypotheses testing and P
values’, ‘sample size calculations’ and ‘comparison of
means’. Future topics to be covered include simple
regression, ... may be inappropriate. For example, non-
parametric methods can be used to analyse alcohol con-
sumption directly using the categories never, a few times per
year, monthly, w...
Báo cáo y học: " Statistics review 11: Assessing risk" doc
... study into early goal-directed therapy in the
treatment of severe sepsis and septic shock by Rivers and
coworkers [5], one of the outcomes measured was in-
hospital mortality. Of the 263 patients ... in-
hospital mortality. Of the 263 patients who were randomly
allocated to either early goal-directed therapy or standard
therapy, 236 completed the therapy period with the
outcomes shown in...
Báo cáo y học: " Statistics review 12: Survival analysis" ppt
... test.
391
test the null hypothesis that there is no difference between
the population survival curves (i.e. the probability of an event
occurring at any time point is the same for each population).
The ... each
case.
The authors also applied Cox’s proportional hazards analysis
and obtained the results given in Table 6. These results
indicate that both age and long-term oxygen therapy ha...