psychology- research methods page ?

what are the other words for psudo participents

actor

stooge

confenderate

what is a orperationalised hypothesis

its a hypothesis that has been written in a testable form and the variabales have to be precisely defined and unambiguous eg adding ages time grams or %

what is a simple hypothesis

a hypothesis tha has not been operationalised

what is a independant variable

this is the variable that the researcher manipulated or changes

what is a dependant variable

this is the variable the research measures

experimantal hypothesis

the experimental hypothesis is a prediction fo what the researcher thinks will happen to the dv when the iv changes (this is operationalised)

what is a null hypothesis

states that the iv will have no effect on the dv and any observed differences will be due to chance

what is a directional hypothesis (one tailed)

predicts the direction of the results difference between 2 conditions or 2 groups of ppts

eg drinking tea improves memory

what is a non-directional hypothesis (two tailed)

predicts that there will be a difference between 2 conditions or groups of ppts with out stating the direction

eg drinking tea affects memory

extraneous variabales

are other variables which must be emiminated or controlled otherwise they may affect the dv and confound results

what r confounding variables

extraneous variabales that skew the results

what is eliminating the confounding variabales

get rid of it altoughether

what is control the confounding variabales

ensure it occurs equaly in each condition

what is experimanter variabales

variabables to do with the resurcher eg parsonality age gender

controlled using standardised procedures like using the same researcher in each condition

what is participant variables

variables to do with the ppts eg gender age intellegance

controlled thru randomly alloccating ppts into conditions so that differnces cancel out

what is situational variables

variables to do with the situation which might interfere or affect the behaviors of the ppts

controlled thru standardised procedures and standardised instructions to ensure that all ppts have exactly the same experience

what is a demand characteristic

when the participants try to find the aim of the research and act accordingly to support or oppose the aim of the research

how r demand characteristics displayed

- guess the purpose of the resurch and trying to please the reasurcher by giving supporting results

- screw u effect

- could act unnaturaly bc of nervousness or fear of evaluation

- acting unaturaly due to social desiarability bias

screw u effect

guess the purpose of the resurch and trying to purposly ruin results

how can demand characteristics be controlled

single blind method

what is single blind method

participants are not told which condition they are in

involves deception - unethical

What are investigator effects?

cues from an investigator that encourage ppts to behave in a particular way

eg tone of voice, body language, facial expressions

investigator effects controlled by

double blind method

what is the double blind method

neither the reasurcher or ppts know what the hypothesis or which condition they are in. a research assistant conducts the research and collects data

what is reliability

consistency of measurement

what is validity

whether a test measures what it says it measures.

internal validity

this is whether or not we can say for certain that the IV has caused the effect seen in the DV

low internal validity (low control) means that there could be a confounding variable

How to improve internal validity

reduce extraneous variables

use standardised procedures (often used in lab experiments)

external validity

the extent results can be generalised to other settings (ecological validity), other people (population validity), and over time (temporal validity)

ecological validity

the extent results can be generalised to other settings

population validity

the extent results can be generalised to other people

temporal validity

the extent results can be generalised over time

How to improve external validity

set experiments in a more naturalistic setting

what is a target population

the group of people the researchers want to apply their results to

what is a sample

- a small number of people from the target population who take part in the investigation

- represents the target population so we can generalise results to the target population

what is sampling bias

may occur if the sample is not representative of the rest of the population

how to avoid sampling bias

make the sample as large as possible

what is random sampling

each member of the population have a equal chance of being selected 'lottery method' eg names in a hat

random sampling pros and cons

pros- best sampling method to generalise results as its unbiased selection of ppts

cons - its long bc u have to get the list of people and then select them randomly

- the sample may still be unrepresentative bc its doesn't ensure an unbiased selection bc the researcher hasn't purposley selected certain characteristics for each condition

what is opportunity sampling

asking whoever happends to be around

opportunity sampling pros and cons

pros- easier and more convenient than random sampling bc the participents are readily available

cons- not likely to be representative bc similar people are around each other and therefore only certain people (with certain characteristics) will take part

- ptts can decline therefore its turns into volenteer sampling

What is volunteer sampling?

Individuals volunteer to be included

volunteer sampling pros and cons

pro- easier and more convenient than random sampling bc ppts go to the researchers themselves

- ppts who want to participate r less likely to sabotage the study (no screw u effect)

con- not likely to be representative bc only certain ppl will volunteer.

- demand characteristics- volunteers r eager to please so give answers to please them

What is systematic sampling?

selected from the target using the nth method

systematic sampling pros and cons

pros- the results high chance of being generalisable bc there can be no researcher bias therefore the sample should be more representitive

cons- sample may still be unrepresentative bc it doesn't assure a unbiased selection

- its difficult with a larger pop as u would need everyones details like with random sampling

what is stratified sampling

small scale reproduction of the pop. it involves diividing it into characteristics important to the study. then the pop is randomly sampled from each catagory

stratified sampling pros and cons

pros - results are unbiased bc they are highly representative due to using a range of subgroups representative of the population for the sample

cons - detailed knowledge ant the pop is needed, however it may not be available bc the data protection laws might stop u accessing nessasary info

- time consuming bc dividing the pop into many catagories and then randomly selecting from each is long

what is primary data

origional data, collected specificaly for the reasurch aim and has not been previously published

what is secondary data

data collected for another research aim and has been published before

meta analysis data

combines data from many studies in similar areas

this allows much larger samples and therefore u can generalise results easier than a sole investigation

what are the summaries of results in descriptive statistics

measures of central tendency

measures of dispersion

percentages

correlation data

what is a measure of central tendency

info about typical scores (averages)

what is a measurment of dispersion

info abt how 'spread out' the scores are (variability)

percentage in descriptive statistics

shows the rate number or amount of something with in every 100. plot on a pie chart

correlation data in descriptive statistics

these studies provide data that can be expressed as a correlation coefficient, which shows either a positive, negative or no correlation. the stronger the correlation the nearer it is to =1 or -1,

plotted on a scattergraph, indicating strength and directing of correlation

What are the measures of central tendency?

mean, median, mode

mean and pros and cons

is the statistical average

pro- uses all the scores so its the most powerful and sensitive

- can be used with interval data

cons- can be distorted by outliers or anomalies making it unrepresentative

- the mean score may not be a actual score for the data

Median and pros and cons

the central value

pros- unaffected by extreme values

- easier to calculate than the mean

- can be used with ordinal data

cons- only takes into account 1 or 2 middle values therefor not as sensitive

- unrepresentataive in a small set of data

mode and pros and cons

most frequently occurring score

pros- unaffected by extreme values. Therefor if data has extreme valued the mode would be better

- easier to calculate than the mean

cons- not good in small sets of data or if there is too many modes

- doesn't take into account other scores

- can be more than 1 mode (bimodal)

what is the measures of dispersion

range

standard deviation

the range pros and cons

pros- quick and easy to work out

- takes full account of extreme values

cons- can be distorted by anomalies

doesn't show if that are clustered or spread evenly around the mean

What is standard deviation?

is a measure of the variability (spread) of a set of scores from the mean

the larger the standard of deviation the larger the spread of scores (more ppts variability)

standard deviation pros and cons

pros- more sensitive dispersion measure than the range since all scores are used in its calculation.

- more accurate bc its uses all the data

- its allows for the interpretation of individual scores

cons- complex to calculate

- less meaningful if the data are not normally distributed

features of lab experiments

- tightly controlled environment

- deliberatly manipulates the IV

- measure the DV

- control extraneous variables

- use standardised procedures

Evaluations of lab experiments

pro- high degree of control bc all variables r controlled leading to greater accuracy and objectivly (internal validity)

- easily replicated to check results

cons - low ecological (external) validity bc artificial and unlike real life. difficult to generalise results to other settings. labs can be intimidating so ppl might act abnormaly

- demand characteristics bc ppts are aware they r being tested and so may unconciously alter behaviour

features of field experiments

- more natural real world environment

- deliberatly manipulates the IV

- measure the DV

- controls some extraneous variables

field experiments

- experiments conducted in natural settings

- manipulates IV measures DV

- controls some extraneous variables

field experiments pros

- greater ecological validity

bc they take place in a real world setting therefore more natural behaviours will be displayed therefore a higher chance of being able to generalise results .

- less demand characteristics

its a natural setting so its less likely to know they r in an experiment and less likely to display demand characteristics as they cannot guess the aim

field experiments cons

- difficult to establish cause and effect

they take place in real world setting where there is less control over extraneous variables therefore it is difficult to establish whether the IV affected the DV

- ethics

ppts not aware they r in a experiment, no informed consent

what r natural experiments

- the IV varies naturaly

- no control over IV

- Measures DV

- no control extraneous variables

what r quasi experiments

- the IV occurs naturaly

- no control over IV

- Measures DV

- no control extraneous variables

natural and quasi experiments pros

- high ecological validity

bc its a naturaly occuring in a natural environment

- no demand charcteristics

bc ppts maybe unaware/resurcher r not present, which avoids demand characteristics and adds to the natural nature of the study

natural and quasi experiments cons

- less control

bc lower control over variables other variables may have caused DV

- ethics

bc lack of informed consent

what r the experimental designs

- independant measures design

- repeated measures design

- matched pairs design

Independant measures design

Using different people in each condition

Independant measures design pros

- quick and easy

time saved bc ppts can be tested at the same time

- avoids demand characteristics

bc less chance ppts can guess study and act accordingly

- no order effects

wont affect results of study bc there arnt any as u only do 1 condition

Independant measures design cons

- need lots of ppts

to get enough data

- ppts variability

this is a problem bc ppt variables might then confound the result

repeated measures design

same people in each condition

repeated measures design pros

- fewer ppts

more data for fewer ppts

- ppts variability

group differences no ppts individuals differnces between conditions

repeated measures design cons

- order effects

ppts do all conditions and so order they do then affect results

- demand characteristics

doing the task twice and migh be able to guess the aim and change behaviour accordingly

- time consuming due to a gap may be needed between conditions to counter the effects of fatigue or boredem

how to over come order effects

counter balancing

what is counter balancing

is where the group of ppts are split into 2 and perfrom the tasks in different order. this ensures that each condition is tested first or second in equal imputs. so differnces cancel out

matched pairs design

uses different ppts in each condition but ppts r matched or paired with another who is similar in a number of variables

matched pairs design pros

avoids order effects and demand characterisrics

- you only take part in 1 condition less likely to know the aim of the study or be effected by the order conditions r done

- ppts variablitily

kept reasonably constant bc u r purposly matching twins based on ppts varibales

matched pairs design cons

- time consuming

bc u need to match ppts on variables

- never perfectly matched

every one is unique