RESEARCH METHODS : PROBABLITIY AND SIGNIFICANCE Flashcards

1
Q

each study has how many hypothesis

A

2

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2
Q

what is an orgianl or alternate hypothesis

A

states there will be an effect

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3
Q

whats the symbol for original or alternate hypothesis

A

H1

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4
Q

What is a null hypothesis

A

states there wont be an effcet

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5
Q

nul hypothesis symbol

A

H0

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6
Q

GIVE EXAMPLE OF ALTERNATE HYPOTHESIS

A

there will be an effect n pt depression score

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7
Q

give example of null hypothesis

A

states there wont be an effect

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8
Q

what do stat test tell us about null hypothesis

A

whether or not to reject null hypothesis

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9
Q

if we reject the nul hypothesis whta does this say about the study

A

good and stat test told me results are good

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10
Q

we look for what rather than truth

A

significance

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11
Q

lets say we find a difference and everyone imporved this dont means the results are …….

because resuts could easily be down to

A

of value/significnat

chance

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12
Q

all studies ewmploy a significance level in order to

A

check for significant differences or relationships

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13
Q

significance levl is the point at which

A

point at wihc researcher can claim to have discovered a large enough difference or correlation within the data to calim an effcet has been found

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14
Q

signficnace level in short

A

point at whihc researcher can reject teh null hypothesis and accept teh alternative hypothesis

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15
Q

stat tests tell us whether

A

reuslts are significant o rnot

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16
Q

what is the accepted level of proability and waht you use unless told otherwise

A

0.05 / 5%

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17
Q

the usual level of signicfane is 0.05 how do you write this properly

18
Q

0.05 is the elvel at whihc waht is accepte

A

alternative/original hypothesis is accepted

19
Q

what doe a 0.05 level of probaility tell us

A

less than 5% proabilty result occured by chance

20
Q

if results come back as significant after conducting a stat test what does this mean probability wise

A

95% proability my result occured due t the manipulation of the IV on the DV ?

21
Q

p of 0.05 measn even if researcher claims to have found asignificant difffrence/correlation

A

there is still up to a 5% chance that it isnt true for the target population in whihc the sample was drawn

22
Q

why cna psycholoigsts never be 100% certain about a particular result

so they have

A

theyve not ested all members of the population under all possible circumnstances - this is not practical economically due to time and costs

so theyve settled on a conventional level of proability where tehyve prepared to accept results may have occured by chance

23
Q

some studies have a 0.001 level of probaility this depdns on

A

what the researchers are trna achieve

24
Q

5% is an accpetable

A

margin of error

25
choosing the wrong significance level can lead to
type 1 error type 2 error
26
what is a type 1 error
when you choose a significance level thats too high such as 0.1/10% the incorrect rejection of a true null hypothesis flase positive
27
what happens when you have a type 1 error
reult in rejecting a null hypothesis thats true fasle positive null hyp rue alt hyp wrong say results are signficant when tehyre actually not
28
what is a tyoe 2 error
the failure to reject a false null hypothesis a false negative when you choose a significance level that is too low e.g 1% or 0.01%
29
what happens when you have a type 2 error
null hypothesis is accepted but alt hypothesis should have been accepted because its true
30
why dopsychologists facour hte 5% level of significance
best balances the risk of making a type 1 or type 2 error
31
once a stat test been calculated whats teh result
a number - calculated value
32
to check for stat significance teh calculated value must be
compared with a critical value
33
what is a critical value
a number that tells us whether or not we can reject the nulll hypothesis and accept eh alternative hypotheis
34
each stat test has its own
table of critical values developed by staticians
35
what is the rule of R
Stat test with the letter R in their name re those where calculated value must be = to or more than critical vlue + there is an r in more
36
how do we know which critical value ot use
one or two tailed test numbe of participants in the study /degrees of freedom level of significance
37
when do we use a one tailed test
directional hypothesis
38
when do we use a two tailed test
non directional hypothesis
39
when and why do probailty levels double
when two tailed test is being used as they are a more conservative prediciton
40
number of pt in the study usually appear as
n value on the table
41
when would a stringetn / low level of singifanec be used e.g 0.01
studies where there may be a human costs such as drug trials or one off studises where for practical reasons cannot be reoeated in teh future
42
what happens if there is a large difference between the calcualted and critical values
in teh preferred direction the researcher will check more stringent levels as the lower the p value the more statistically significnant the result