7- Significance test

Question 1

What is a significance test ?

Answer 1

a statistical procedure for evaluating the plausibility of the null hypothesis.

Question 2

What is another word for statistically significant ?

Answer 2

It simply means unusual. It low for occuring by chance

Question 3

What is a null hypothesis ?

Answer 3

a hypothesis about the distribution of scores from which a sample was drawn.

Question 4

What is the formula for zobs?

Answer 4

m-mew/om

Question 5

What is z obs ?

Answer 5

A test statistic

Question 6

What is a test statistic ?

Answer 6

is computed from a sample statistic, such as the sample mean.

Question 7

We say that a statistic is statistically significant when…

Answer 7

it has a low probability of occurrence under the null hypothesis.

Question 8

What is a p-value ?

Answer 8

It expresses the probability of a statistic, or one more extreme, occurring by chance when the null hypothesis is true.

Question 9

When rejecting a null hypothesis we treat is as…

Answer 9

Tough

Question 10

When a hypothesis is plausible we…

Answer 10

Retain it. It just mean that evidence (zobs) is not sufficient for us to treat it as implausible.

Question 11

What is the criterion for significance of the p-values ?

Answer 11

less than 0,05 are statistically significant and more than 0,05 are not !

Question 12

You want your p-value to be … as possible to be significant

Answer 12

smaller

Question 13

What are directionnal tests ?

Answer 13

make predictions about whether a statistic will be greater or less than a specified parameter.

Question 14

Directional tests are also called…

Answer 14

One tailed tests

Question 15

What are non-directionnal tests ?

Answer 15

make no prediction about whether a statistic will be greater or less than a specified parameter. The p-value associated with a test statistic (such as zobs) is the area in two tails of the distribution

Question 16

What are non-directionnal tests called ?

Answer 16

Two tailed tests

Question 17

How do you compute the interval for z obs ?

Answer 17

2* P(zbs)

Question 18

Any zobs outside the interval ±1.96 will be…

Answer 18

statistically significant

Question 19

Any zobs within the interval ±1.645 will…

Answer 19

not be statistically significant

Question 20

What is z critical ?

Answer 20

is the z-score that zobs must exceed for us to reject the null hypothesis. By exceed we mean further from 0 than the criterion.

Question 21

What is H0: ?

Answer 21

symbolic name for the null hypothesis, and the colon (:) is a way of saying, “what follows.”

Question 22

How is the alternative hypothesis called ?

Answer 22

The research hypothesis !

Question 23

How do you express the null hypothesis, when two populations are considered ?

Answer 23

H0: mew1 = mew0

or

H0: mew1-mew0=0

Question 24

What is the symbol to alternative hypothesis ?

Answer 24

H1

Question 25

How do you write the meaning of a p-value ?

Answer 25

p= Pr (statistic | Hypothesis).

ex: .0062 = Pr(2.5 |H0).

Question 26

What is the inverse probability error.

Answer 26

p = Pr(Hypothesis |Statistic).

IT IS WRONG