Making Inferences: Confidence Limits and Statistical Significance Flashcards
the name given to the standard
deviation of the sampling distribution.
standard error
probability always goes from____
0 to 1
*that is if we carry out the same experiment over and
over again we will get slightly different results every
time.
The SE is the SD of that sample of scores.
An event which has a probability of____ will not happen.
zero
probability of a result occurring if
the null hypothesis is true, not the probability that the
null hypothesis is true.
Probability value
if we are
looking for a result in one direction only.
One tailed (or directional) hypothesis
An event which has a probability of ____ will happen, no
matter what.
1
______is counter-intuitive.
probability
It is ______ because we like to believe that we
know things rather than making probability statements
about them.
counter-intuitive
symbolized by H₁. The
hypothesis that claims the differences in results between
the conditions is due to the independent variable.
alternative hypothesis
value or cut-off we use
before we decide to reject the null hypothesis.
α (alpha – Greek Letter)
symbolized by Hₒ. Logical counterpart
to the alternative hypothesis. It either specifies that
there is no effect, or that there is real effect in the
direction opposite to that specified by the alternative
hypothesis.
null hypothesis
When the probability is found to be below 0.05 (or
whatever cut-off we are using) it is described as____
statistically significance
somewhat arbitrary, but is the
convention that is used throughout much of science.
0.05 (1 in 20 0r 5%) –
is deemed rare enough that we can trust it
but not so stringent that it is impossible to achieve.
one in 20
if we are
looking for a result in either direction.
Two-tailed (or non-directional) hypothesis
Psychologists accept findings that are likely to have
occurred by chance no more than 5 out of 100 times.
(P = to or < .05)
Determining how likely it is that the result could have
occurred by chance.
statistical significance
the probability that the
pattern of data that was observed did not occur by
chance.
statistical significance
indicates that the probability that the
observed finding occurred by chance is less than 5 in
100.
alpha level
A statistically significant result does not necessarily
have “meaning”, and is not necessarily “important”, it
just means that there is a less than 1 in 20 probability
that the results would have occurred if the______were correct.
null hypothesis
If you find that your p-value is below 0.05, you reject
the null hypothesis. This does not mean to say that you
can accept the _____
alternative hypothesis
the range of values which are
the likely range of the population value.
Confidence Intervals
Similarly, if you find that your p-value is above 0.05, you
can not say that you can accept the_____. All
you can say is you have not found evidence to reject it
null hypothesis.
accept the null hypothesis
accept the alternative hypothesis
reject the alternative hypothesis
wrong
when we reject the null hypothesis
because there is only a low probability of the result
occurring if it is true, but it might actually be true after
all.
type 1 error
reject the null hypothesis
fail to reject the null hypothesis
correct
value that we suspect in the population
mean
– the other logical error when we fail to
reject the null hypothesis when it is not true.
type II error
If we want to estimate the statistical significance of our
results (that is, the probability of our result occurring if
the null hypothesis is true), then we need to get back to
the_____
standard error
If our sample is large, the distribution will be normal.
central limit theorem
If our sample is not large, then the distribution is not
normal, instead it follows a shape called the____
t-distribution
value for our mean in the sample
score
– the number of scores that
are free to vary in calculating a statistic.
df = N – 1
Degrees of Freedom or df
the largest and smallest values in the interval.
Confidence Limits
We usually calculate 95% confidence limits which match
the 0.05 significance level
(alpha level α )
