1
Q
Probabilidad objetiva y subjetiva
A
2
Q
Empirical probability dado STATA
A
3
Q
Binomial probability
A
4
Q
Binomial probability
A
5
Q
Binomial probability
A
6
Q
Poisson
A
7
Q
Poisson
A
8
Q
A
9
Q
Bar graph binomial distribution
A
10
Q
Poisson formula
A
11
Q
A
12
Q
En STATA
A
13
Q
A
14
Q
A
15
Q
2 dice in STATA
A
16
Q
PROBABILITY PROBLEM
A
17
Q
A
18
Q
A
19
Q
STATA IS LEFTLIST
A
20
Q
A
21
Q
Pnorm graphs to check normality should be used with… sample sizes
A
Large
22
Q
In medicine we usually have a long R tail, so we use transformations of the variable so that they can follow a normal distribution
A
23
Q
NORMAL DISTRIBUTION SUMMARY
A
24
Q
A
Random error
25
Systematic error-bias
26
Sampling in STATA
27
Sampling in STATA
28
Para no perder el trabajo cuando hacemos RANDOM SAMPLING IN STATA, debemos usar los comandos…
preserve
….
restore
29
Count
30
Random allocation “randomization”
31
RANDOMIZATION IN STATA
32
What can you do to get again exactly the same random allocation or the same random sampling in STATA?
Set seed 9999
33
In internal validity, what is more important? Biological inference or statistical respresentativeness?
BIOLOGICAL INFERENCE: for causal inference.
Representativeness can become a fallacy and it is needed for external validity.
34
REPLICAR EL CENTRAL LIMIT THEOREM EN STATA: sacar una muestra y su media
35
PROBABILITY INTERVALS VS CI (VERY IMPORTANT)
With age we cannot apply normal distribution, it is calculating a probability interval. We can only calculate the CI with a sample in ESTIMATORS.
36
37
¿Qué observamos?
200 intervalos de confianza del 95% para la media de edad calculados en 200 muestras, cada una de 36 sujetos.
AL FINAL TENEMOS 5 CI WHICH FAIL, NO TOCAN LA REALIDAD, por ello 95% CI.
38
PROBLEMA RESUELTO CON DISTRIBUCIÓN NORMAL Y BINOMIAL
39
PROBLEMA A RESOLVER CON NORMAL Y POISSON
40
41
42
Probability following a normal distribution
43
SE
44
45
46
47
48
T tail STATA
49
Rejecting the null hypothesis
50
Hypothesis testing for a proportion
51
Hypothesis testing for a proportion in STATA
Always look at 2-tailed
52
Hypothesis testing for a mean
53
INTERPRETACIÓN p value
54
Two-sample test of proportions in STATA
55
Z test for proportions in STATA
56
Chi 2 en STATA
57
Getting expected values in STATA
58
If expected values in chi are lower than 5, what do we use?
FISHER EXACT TEST
59
Pearson chi 2 with rows and columns
Here we have 3 DF.
En la última foto, a la izquierda sacamos expected values y a la derecha observed
60
Chi 2 y z with only one variable and many categories
61
Mc Neman paired test for proportions
62
Chi2 for linear trend
1df, ordinal variables
63
T test parametric indecent variables STATA
64
corregir CI en t-test
65
F distribution para comparar SD, si es mayor que 0.05 cumple homogeneidad.
Mirar t-tail más pequeña
66
Sd test con calculadora en STATA
67
T test heterogeneous variances STATA
68
Paired T-test en STATA
69
Paired t test but with mean vs external reference
70
ESQUEMA COMPARISON OF MEANS
71
Mann Whitney U test STATA
RESEARCH METHODOLOGY
flashcards
Decks in class (19)
# Cards
-
CLASS 14: TAXONOMIC AXES EXERCISES16
-
CLASS 17, 18, 19 EXERCISES15
-
CLASS 20 and 21 EXERCISES10
-
CLASS 22, 23, 2415
-
PROBABILIDAD71
-
STATA CONCEPTS23
-
NON-PARAMETRIC TESTS (Comparison Of 2 Means)9
-
SAMPLE SIZE13
-
ANOVA ONEWAY AND FACTORIAL (TWOWAY, R.M, ANCOVA)41
-
CORRELATION11
-
REGRESSION8
-
SURVIVAL ANALYSIS12
-
CLASS 61 AND 62: SYSTEMATIC AND RANDOM ERRORS18
-
CLASS 63: CONFOUNDING VARIABLES5
-
MULTIVARIABLE MODELS23
-
CONFOUNDING VS INTERACTION9
-
EXAM TYPE QUESTIONS14
-
Class 68 And 6913
-
STROBE CHECKLIST2
