MD EVIDENCE BASED DENTISTRY Flashcards by Hisham Abughoush

HEIRCHY OF EVIDENCE:

BEST AND WORS TYPE OF STUDY?

Best: META ANALYSIS (analysis combines multiple studies)

Worst: IN VITRO STUDIES (test tube)

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epedemiological studies

quantify disease status in a community

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survey or measurement taken to represent a snapshot in time, prevelance

case control study

cross sectional study

prospective cohort study

retrospective cohort study

CROSS SECTIONAL

same day sudy

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people with a condition are compared to people without it (control) in the past, odds ratio

case control study

cross sectional study

prospective cohort study

retrospective cohort study

CASE CONTROL STUDY

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cohort followed thorugh time to see who develops a diseae, incidence and related risk

case control study

cross sectional study

prospective cohort study

retrospective cohort study

PROSPECTIVE COHORT STUDY

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look back after following cohort and decide what disease you want to look for, incidence and relative risk

case control study

cross sectional study

prospective cohort study

retrospective cohort study

RETROSPECTIVE COHORT STUDY

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A scientist wanted to do a study on how many alcholohic patients have oral cancer so he took a sample size of an area.

case control study

cross sectional study

prospective cohort study

retrospective cohort study

CROSS-SECTIONAL STUDY ( survey to find prevelance)

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a researcher is trying to find link between tobacco smoking and lung cancer

case control study

cross sectional study

prospective cohort study

retrospective cohort study

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purpose of analytical and observational studies?

detemrine the etiology (cause) of disease

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what is the purpose of CLINICAL TRIAL?

isolate one factor and examine its contribution to patients health by holding all other factors as constant as possible

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best tool for doing an experimental study?

RANDOMIZATION

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best type of clinical trial to do

single blind

double blind

random sampling

random allocation

DOUBLE BLIND !!

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for frequency distributions, what is the shape of NORMAL DISTRIBTUION?

BELL SHAPED

IMAGE : bell shape is middle red

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How do we measure the RANGE of a set of numbers?

maximum - minimum = range

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how spread out individual values are from the mean is called what?

VARIANCE

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square root of vairance is called what?

standard Deviation

how do we find SD?

squar root of variance

what does a large SD tell you about numbers?

the larger the SD the more spread out the number are

reliability and validity:

which one is precicision and which one is accurate?

Reliability: Precision

Validity: accuray

KNOW THIS CHART !!!

High TN related to FP: High specificity

High amount of TP relative to FN: high sensitivity

Success: HIGH TP and TN

FAILS: FP and FN

How is STATISTICAL SIGNFICANCE (P-VALUE) defined?

probability 2 variables UN-RELATED

what do you do about the null hypothesis if p< .05?

reject null hypothesis: statistically significant

null hypothesis: soemthing we belive to be true!

JOn says they have a good technique to roll a 6 on a dice more frequently.

Null hypothesis: researcher states no relationship between technique you use and rolling a 6 ( believed it to be true)

jon poes null is rejected because means likely that he is right

average male baby in texas is 7 lbs. a nurse suspects that baby weight has went up in recent years and collect data to see.

null hypothsis (scientist) H₀: 7 lbs

alternative hypothesis (midwife) H₁: >7 lbs

NULL HYPOTHESIS IS WHAT WE EXPECT TO SEE BASED ON KNOWLEDGE WE HAVE

midwife wants null rejected.

what does the researcher try to do to the null hypothesis ?

disprove, rejectm or nullify

THERE IS NO DIFFERENCE B/W CARIES PREVELANCE IN FLUORIDATED VS NON FLUORIDATED WATER What is the null? when is the null hypothesis rejected? when is null accepted? what is a type 1 and type 2 error

EXTREMELY IMPORTANT !!! Null: no difference b/w fluoridated vs nonfluoridated Reject null: there is a difference when its rejected: True positive **TYPE 2 ERROR** : *accepted* null that shouldve been rejected **TYPE 1 ERROR :** *rejected* null whenever it was true We accepted null hypothesis: when there is true negative

what is a type 1 error ;

when we **REJECT** null whenever it is **TRUE**

what is type 2 error?

ACCEPT null whenever it should be REJECTED

what is correlation coefficent (r) ?

measure represents strength of relationship b/w 2 quantitative variables always between : -1 and 1 -1 (lie on perfect negative line) +1 (lie on perfect positive line) r=0 means no linear relationship

measures association b/w 2 categorical values ? T-Test Z-test ANOVA CHi-squared test (X²)

chi-squared ex: prefer cats or dogs both men and women

measures statistical differences b/w 2 means, small sample size T-Test Z-test ANOVA CHi-squared test (X2)

T-test if T-value lower than number then dont rekect null if higher then reject.

measures statistical differences b/w 2 means, large sample size T-Test Z-test ANOVA CHi-squared test (X2)

Z-test

used to test differences between 2 or more means T-Test Z-test ANOVA CHi-squared test (X2)

ANOVA( analysis of variance)

match: qualitative, quantitative Descriptive, numbers

qualitative: DESCRIPTIVE quantitative: numbers

what test is for qualitative vs quantitiatve? X² T-test Z-test NOVA

qualitative: X2 quantitative: t test/ z test/ nova

hair type, blood type, etc is a type of what? qualitative or quantitative

qualitative (**NOMINAL**): names and labels

which is qualitative and which is quantitative? give examples ordinal interval nominal ratio

**Qualittive:** nominal (names or labels): hair type, blood type etc ordinal (ranking): socioecnomic status, educational level etc. **Quantitative:** _ordinal_: ranling _interval_ (value range; measure on scale): temp, sat scores _ratio_: range of values with clear definition of 0: rxn rate, pulsem weight

X and Y: whch one is independent and dependent

X: indepepndent Y: dependent

WHAT ARE COMPONENTS OF SCIENTIFIC PAPER IN ORDER ??? BOARD \*\*\*\*

TITLE ABSTRACT (summary; spark notes) INTRODUCTION METHODS (info about pop being tested) RESULTS DISCUSSION CONCLUSION REFERENCES TAIMR-DCR