[L4] Making Inferences Confidence Limits and Statistical Significance

Question 1

the name given to the standard
deviation of the sampling distribution.

Answer 1

Standard Error -

Question 2

*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 ___ of that sample of scores.

Answer 2

SD

Question 3

Formula of Standard Error

Answer 3

se = σ / √ N

Question 4

A probability always goes from ___

Answer 4

0 to 1.

Question 5

An event which has a probability of ___ will not happen

Answer 5

zero

Question 6

An event which has a probability of __ will happen, no
matter what.

Answer 6

1

Question 7

Probability is ___ we like to believe that we
know things rather than making probability statements
about them.

Answer 7

counter-intuitive

Question 8

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.

Answer 8

Null Hypothesis

Question 9

The
hypothesis that claims the differences in results between
the conditions is due to the independent variable

Answer 9

Alternative hypothesis –

Question 10

___– if we are
looking for a result in one direction only.

Answer 10

One tailed (or directional) hypothesis

Question 11

– value or cut-off we use
before we decide to reject the null hypothesis.

Answer 11

α (alpha – Greek Letter)

Question 12

____ probability of a result occurring if
the null hypothesis is true, not the probability that the
null hypothesis is true

Answer 12

Probability value –

Question 13

0.05 (1 in 20 0r 5%) – somewhat ___, but is the
convention that is used throughout much of science.

Answer 13

arbitrary

Question 14

____ is deemed rare enough that we can trust it but
not so stringent that it is impossible to achieve.

Answer 14

One in 20

Question 15

When the probability is found to be below 0.05 (or
whatever cut-off we are using) it is described as
___

Answer 15

statistically significant

Question 16

the probability that the pattern
of data that was observed did not occur by chance.

Answer 16

Statistical Significance –

Question 17

Psychologists accept findings that are likely to have
occurred by chance no more than __out of 100 times.
(P = to or < .05)

Answer 17

5

Question 18

– indicates that the probability that the
observed finding occurred by chance is less than 5 in
100.

Answer 18

Alpha level

Question 19

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.

Answer 19

Type I Error –

Question 20

– the other logical error when we fail to
reject the null hypothesis when it is not true.

Answer 20

Type II Error

Question 21

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 ___

Answer 21

standard error.

Question 22

If our sample is large, the distribution will be ___

Answer 22

normal.
(central limit theorem)

Question 23

If our sample is not large, then the distribution is not
normal, instead it follows a shape called the ___

Answer 23

t-distribution

Question 24

___– the number of scores that
are free to vary in calculating a statistic.

Answer 24

Degrees of Freedom or df

Question 25

__ the range of values which are
the likely range of the population value.

Answer 25

Confidence Intervals –

Question 26

the largest and smallest values in
the interval

Answer 26

Confidence Limits –

Question 27

We usually calculate __confidence limits which match
the __- significance level (alpha level α )

Answer 27

95% ; 0.05

Question 28

In 95% of studies, the true
(population) mean will be contained within the
confidence intervals.

Answer 28

Correct interpretation

Question 29

There is a 95 % chance that the
true (population) mean is contained within the
confidence intervals.

Answer 29

Wrong interpretation:

Question 30

The___ cannot change! – it is fixed. It is
either within or not.

Answer 30

population mean

Question 31

____are two
sides of a coin.

Answer 31

Confidence Intervals and Statistical Significance

Question 32

If the CIs contain the null hypothesis, the result is

Answer 32

not
statistically significant.

Question 33

If the CIs do not contain the null hypothesis, the result is

Answer 33

statistically significant

Question 34

if we are
looking for a result in either direction.

Answer 34

Two-tailed (or non-directional) hypothesis –