Mathmatics and Research Methods (MCAT)

control

controls are important for comparing things

you can be your own control if tested before and after a treatment

ratios control for variation

using a ratio measurement or a baseline comparison helps control for differences in cell count, conditions, etc.

autoclave

kills everything

you can autoclave a biohazard bag

variables

mediating variable- explains the relationship between independent and dependent variable

confounding variable- influences both the independent and dependent variable

best experiment to prove a hypothesis

do an experiment with and without a certain variable to establish the strongest evidence for cause-effect

all other variables are kept the same

best treatment

proactive treatment is better than reactive treatment

even better if its specific, targeted with no side effects

which result does not validate results

pick the answer that directly contradicts the data in the passage, no just that one that isn't supported

odds ratio

Ratio of the odds occurring in one group vs. the odds occuring in another group

mortality/morbidity

mortality- deaths by disease during a time interval

morbidity- either incidence or prevalence

incidence- new cases of disease during a time interval

prevalence- how many total people have a disease

survey biases

subjective bias- self-reported

social desirability bias- participants deal with sensitive/ethical subjects

selection bias- participants are usually self-selected

attrition bias- participants drop out of study over time

validity

construct validity- whether a measurement actually measures the variable/construct being studied

criterion validity- whether a test correlates with other existing tests or measurements

external validity- generalizing results to other people and situations

internal validity- extent of causation proved

ecological validity- whether experiment replicates real-world conditions

reliability

Ability of a test to yield very similar results over repeated testings

correlation

A measure of the extent to which two factors vary together, and thus of how well either factor predicts the other

R = 0 means no relationship
R = 1 means perfect relationship
R = -1 means perfect inverse relationship

rearranging equations

to calculate a variable, rearrange equation so all other variables are on the other side

calculating units

always write units on your numbers, check the units in the question and the answers

for area and volume, conversion values are ^2 or ^3
1 m = 10^2 cm
1 m^3 = 10^6 cm^3

operationalization

the process of turning an abstract variable into a measured or manipulated variable, even if cannot be quantified directly

causation

need a control without the variable to prove causation

usually unethical in psychology and sociology experiments

controlling

eliminate influence of confounding variables, isolate the variable of interest

methodological limitations

sampling biases
confounding variables

counterbalancing

using subjects as their own control group by having half of them be experimental first and half of them be control first

controls for the order of tests presented
fatigue and boredom can affect test performance over time

supporting vs. elaborating

supporting- discussing details and evidence to support a point

elaborating- explaining in more depth

ethics

participants must volunteer, can withdraw at any time

shocking people is ethical as long as you have consent

ethnography

observing social interactions in real social settings

long term studies

cross-sectional study- one point in time
cohort study- longitudinal study follows group over time

observational study

attempts to determine relationships between variables, but the researcher imposes no conditions as in an experiment

median

reduces influence of outliers when compared to the mean

sampling

pick sample that represents population you want to study

flaws in research

both internal and external validity are flaws

its it generalizable

is it proving causation

temporal

independent variable needs to be measured before the dependent variable

surveys

are cheap and easy

biographical sketch

study environmental influences of behavior

necessary and sufficient

necessary- without it, no effect

sufficient- with it by itself, has effect

knockout genes

-/-
+/+ have both alleles (WT)

precision and accuracy

get a larger sample size