the relationship between a statistic and a parameter is the same as the relationship between...
a sample and a population
in a correlational study...
2 variables are measured and there is only 1 group of participants
what additional info is obtained by measuring two individuals on an interval scale compared to an ordinal scale?
the size of the difference
a characteristic, usually a numerical value, which describes a sample is called...
statistic
the natural difference that exists between a sample mean and the corresponding population mean
sampling error
what kind of study is used to examine the relationship between two variables but can't determine whether it is a cause and effect relationship
correlational study
in a positively skewed distribution, scores with the highest frequencies are...
on the left side of the distribution
the value for SS, variance, and standard deviation are never...
negative
under what circumstance is the median likely to produce a better measure of central tendency than the mean...
with an extremely skewed distribution
the critical region describes outcomes with...
a very low probability if the null hypothesis is true
increasing the alpha level from 0.01 to 0.05 means...
increase the likelihood of rejecting null and increase the risk of a type I error
the power of a statistical test is the probablity of
rejecting a false null hypothesis
alpha represents...
-amount of type I error you are willing to risk
-the probability associated with region(s) of rejection
-significane level
resulting N, when other factors are held constant, means...
-larger z-score
-increased ability to reject null
standard error
measures the average size of the difference between a sample mean and the population mean
under what circumstances will the distribution of sample means be normal?
if the population distribution is normal or if the sample size is quite large (ie. atleast greater than 30)
if a treatment has no effect it's possible to obtain an extreme sample mean that is very different from the population mean, the outcome that is likely to happen is...
reject null and make a type I error
what is the consequence of making a type II error
concluding that a treatment has no effect when it really does
when can a very small treatment effect still be significant
if the sample size (n) is very large
a hypothesis test involves a comparison of what two elements
research results from a sample and a hypothesis about a population
what happens to the expected value of M as sample size increases
it stays constant
what happens to the standard error of M as sample size increases
it decreases
a dot cluster (scatterplot) that tilts from the upper left to lower right reflects
a negative relationship
a value of r in excess of 0.50 in either a positive or negative direction would represent...
a very strong relationship in most areas of behavioral research
when the range of possible x and or y scores is restricted, the value of the correlation coefficient usually...
decreased
dots in scatterplots that deviate conspicuously from the main dot cluster are viewed as...
potential outliers
in a scatterplot predictive errors are
associated with vertical discrepancies (distances) between dots and the regression line
the spearman correlation should be used...
when the original data are measured on an ordinal scale of measurement
if the pearson line between the x and y is positive tha...
the regression equation will have a positive slope
f test is looking for any difference among group or condition means...
always considered to be non-direcitonal test
in anova independent variables are called
factors
when tukey's hsd is used two means are significantly different if the absolute difference between them is...
greater than the HSD
post-hoc comparisons are used in one-way ANOVA to compare all of the possible paris of...
sample means from different levels of a factor to determine which are significantly different from each other
what is stated by the null hip for an ANOVA
there are no differences between any of the population means
the null hypothesis presumes that any observed difference between sample means in an independent sample t test or in anova...
reflects sampling variablility
use ANOVA whenever the hypothesis makes a claim about...
difference among more than two population means
in anova if a treatment effect exists...
variability between groups will tend to exceed variability within groups
following an F test the squared the curvilinear correlation indicates...
the proportion of variance in dependent variable attributable to the independent variable
after rejecting the null hyp in ANOVA we then calculate...
tukey's hsd
-helps us evaluate whether specific differences among pairs of group (or condition) means are significant