Researcher draws inferences regarding a hypothesis about a population.
Describe Alternative Hypothesis
the hypothesis that claims that the effect on the dependent variable is due to the independant variable.
Describe Null Hypothesis
Whatever effects there are on the dependent variable are NOT due to the independent variable but are due to chance.
If the NULL is FALSE the alterantive is TRUE
Alpha Level
The level to which a researcher limits the probability of rejecting the null hypothesis when it is true.
(Type 1 Error)
Type 1 Error
A decision to REJECT the NULL when it is in fact true.
(results are due to chance, yet you still conclude they are due to the independent variable)
Type 2 Error
A decision to RETAIN the NULL when it is false.
(to conclude results are due to chance when they are in fact due to the independent variable)
Significant result
Null has been rejected and the alternative has been retained.
Steps to Calculate POWER with a SIGN Test
1) Assume Null is true. 50/50
Create grid:
outcomes
sum of outcomes
greater than alpha?
2) for each P event use the equivelent Q event
on table B locate the Q event at the percentage of 100-preal
Add the outcomes percentages
IF 2 TAIL double the answer
Factors increasing POWER
1) Increase N
2) as p-real deviates father from .50
3) as alpha increases
4) when we use a 1 tail test (not 2 tail)
Power
the probability that the results of an experiment will allow the rejection of the null hypothesis if the independent variable is true.
real effect
an effect that produces significant change in the dependent variable
P -NULL
the probability of getting a plus with any participant in the sample of an experiment when the independent variable has no effect (ALWAYS .50)
P-REAL
The probability of getting a plus with any participant in the sample of an experiment when the independent variable has a reall effect.
Sampling distribution of a statistic
1) Gives all the values that the statistic can take
2) Gives the probability of getting each value under the assumption that it resulted from chance alone.
Sampling distribution of the mean
Gives all the values that the mean can take and the probability of getting each value if the sampling is done at random from a population where the independent variable has no effect
Critical region for rejection of the null hypothesis
Area under the curve that contains all the values of the statistic taht allow rejection of the null hypothesis
Critical value of a statistic
the value of the statistic that bounds the critical region