Lecture 0: Lab Techniques

Question 1

Independant vs dependant variables

Answer 1

1. Independant: whats manipulated/ x axis
2. Dependant: whats measured/ y axis

Question 2

Confounding variables

Answer 2

1. Unmeasured variables that affect dependant variable

Question 3

Categorical vs quantitative variables

Answer 3

1. Categorical
   1a. Nominal: names
   1b. Ordinal: numbers that dont have value (categories 1-2)
2. Quantitative
   2a. Ratio: start is 0
   2b. Interval: has no 0/something that is relative to each other

Question 4

Experimental studies

Answer 4

1. Scientists modify 1+ variables to test hypothesis
2. Use controls
   2a. Negative controls: not expected to produce results (placebo)
   2b. Positive controls: expected to produce known results

Question 5

Recruitment methods

Answer 5

1. Probability sampling
   1a. Simple random sampling: selecting participants randomly
   1b. Cluster random sampling: select clusters (groups similar to each other) randomly (same small group)
   1c. Stratified: different small groups
2. Non probability sampling
   2a. Snowball sampling: initial participants found…they then refer researchers to other similar participants

Question 6

Blinding

Answer 6

1. Important for experimental studies to be unbiased
   1a. Double blind or single blind

Question 7

Observational studies

Answer 7

1. Often correlation studies (seek to correlate 2+ variables)
2. Types
   2a. Cross sectional: a lot of people at same time
   2b. Longitudinal: small group over long period of time
   2c. Case control studies: only for rare cases
   2d. Quasi experimental studies: often longitudinal to observe natural experiments (experiments applied not randomly)
   2e. Case studies: follows few cases

Question 8

Measures of central tendency

Answer 8

1. Mean: average
2. Median: middle
3. Mode: most common number

Question 9

Skewing a bell curve

Answer 9

1. If mean=low: left skewed
   1a. If median on box plot is higher=data skewed left
   1b. If median on box plot is lower=data skewed right

Question 10

Measuring dispersion

Answer 10

1. Standard deviation: higher #=more dispersion

Question 11

Accuracy vs precision

Answer 11

1. Accurate: getting the correct number
2. Precision: all values calculated are similar

Question 12

Research biases

Answer 12

1. Observer bias: observer records data incorrectly
2. Subject bias: subjects misrepresent data

Question 13

P value

Answer 13

1. If p<0.05: results are significant and not due to chance

Question 14

Error types

Answer 14

1. Type 1: false positive (say you have a disease but you dont)
2. Type 2: false negative (say you don’t have a disease but you do)

Question 15

Correlation

Answer 15

1. If correlation coefficient is near -1 or 1=strong correlation

Question 16

Validity

Answer 16

1. Internal validity: degree where independant variables are demonstrated to cause the dependant variable (confounding variables threat this)
2. External validity: ability of researcher to provide results that can be generalized to real like situations

Question 17

Inductive vs deductive reasoning

Answer 17

1. Inductive: evidence first
2. Deductive: rules first