Research Methods (Ch. 18)

one-shot studies

(pre-experimental) a group of participants receives a treatment followed by a test to evaluate treatment

one-group pretest-post-test design

(pre-experimental) very weak, is better than the one shot design. at least we can observe any change in performance has occurred

3. the laboratory supervised endurance exercise with motivational support plus the interaction of a selection bias (all participants were baseball pitchers from Marshall High School) are the threats to _______.

external validity

quasi-experimental design

a research in which the experimenter tries to fit the design to real-world settings while still controlling as many of the threats to internal validity as possible

line

group of participants

dotted line

intact

1. a double blind-experiment is one in which ________.

neither the researcher nor the participants know which participants receive the experimental treatment

O

observation or a test

if the condition is necessary and sufficient to produce the effect...

then it is the cause

3 criteria for cause and effect

1. cause must precede effect 2. cause and effect must be correlated with each other 3. the correlation between cause and effect cannot be explained by another variable (elementary school and shoe size, third variable is age)

threats to internal validity

1. history 2. maturation 3. testing 4. instrumentation 5. statistical regression 6. selection biases 7. experimental mortality 8. selection-maturation interaction 9. influence of experimenters on participants

types of validity

1. internal: did the treatments cause the change in the outcome? 2. external: to what populations, setting, or treatments can the outcome be generalized

pre-experimental

1. one-shot studies 2. one-group pretest-posttest 3. static group comparison

types of designs

1. pre-experimental designs 2. true experimental designs

controlling threats to internal validity

1. randomization 2. placebos 3. blind setups 4. double-blind set ups 5. reactive effects of testing: eliminating pretest 6. experimental mortality

true experimental designs

1. randomized-groups design 2. pretest-posttest randomized groups

threats to external validity

1. reactive or interactive effects of testing 2. interaction of selection biases and treatment 3. reactive effects of experimental agreements 4. multiple-treatment interference

controlling threats to external validity

1. selecting from larger population 2. ecological validity

how experimental research tries to establish cause and effect

1. selection of a good theoretical framework 2. application of appropriate experimental design 3. use of correct statistical model and analysis 4. proper selection and control of independent variables 5. appropriate selection and measurement of dependent variables 6. correct interpretation

2. the one characteristic of true experimental designs that pre experimental and quasi-experimental designs do not have is ________.

random assignment to groups

R

random assignments of participants to groups

T

signifies that a treatment is applied