Test 3.2 Flashcards
A study based on another study that uses different methods, a different manipulation, or a different measure.
conceptual replication
Repeating a study using the same means of manipulating and measuring the variables as in the original study.
exact replication
A study that varies from an original study in one systematic way- for example, by using a different number or type of subjects, a different setting, or more levels of the independent variable.
systematic replication
A parametric inferential statistical test of the null hypothesis for a single sample where the population variance is not known.
t-test
______ is a means of determining the number of standard deviation units a score is from the mean (µ) of a distribution.
t test
With a t test, the _________ is not known
population variance
The t test typically involves using smaller samples (N
30
The number of scores in a sample that are free to vary
degrees of freedom
_______= N-1
degrees of freedom (df)
When the sample size is large, the t distribution is the same as the z distribution.
True or False
True
If t = +2.06, it means that _____
our sample mean falls 2.06 standard deviations above the population mean.
A parametric inferential test for comparing sample means of two independent groups of scores.
independent-groups t test
Indicates whether the two samples perform so similarly that we conclude they are likely from the same population or whether they perform so differently that we conclude they represent two different populations.
independent-groups t test
The standard deviation of the sampling distribution of differences between the means of independent samples in a two-sample experiment
standard error of the difference between means
If t obt= 4.92 Spaced study has 10 people Massed study has 10 people a= .05 one tailed Ho: µ1≤µ2 Ha: µ1>µ2 do we reject of fail to reject the null hypothesis?
1-tailed test, so we have 18 degrees of freedom, we reject the null hypothesis, bc the critical t is 1.734, and so Our t obt is larger than the critical t and so we support the alternative hypothesis. The results are significant at the .05 level.
The results would be
t(18)=4.92, p
When a result is significant, the p value is reported as ______ .05.
less than
We want the probability to be ______.
small, because we want to be confident that there is only a small probability that our results were due to chance. This means it is highly probable that the observed difference between the groups is a meaningful difference and actually due to the IV.
We want the t score to be ______.
large to increase the chance that it will be significant.
What will increase the size of the tscore?
anything that increases the numerator or decreases the denominator in the equation.
What will increase the numerator?
a larger difference between the means for the two groups (a greater difference produced by the independent variable). This difference is somewhat difficult to influence. However, if we minimize chance in our study and the IV truly does have an effect, then the means should be different.
What will decrease the size of the denominator?
Because the denominator is the standard error of difference between the means and is derived by using s (the unbiased estimator of the population standard deviation), we can decrease by decreasing the variability within each condition or group or by increasing the sample size.
What three aspects can increase power?
- greater differences produced by the IV (increase numerator)
- less variability of raw scores in each condition (decrease denominator)
- increased sample size (decrease denominator)
In creating a graph, we place the _____ on the x-axis and the ____ on the y-axis.
IV on x-axis
DV on y-axis