ECON 2843 TEST 3 BRENT NORWOOD EXAM QUESTIONS
AND CORRECT ANSWERS
What does a one way anova test tell you? - ANSWER it tells you a yes or no answer on
whether one group is different from the other
what does a two way anova test tell you? - ANSWER it conditions groups based on TWO
facors rather than one
when is it appropriate to use a TWO way ANOVA test? - ANSWER when you REJECT the
NULL on a one way
is SSTR between groups or within groups - ANSWER BETWEEN
Is SSE between groups or within groups? - ANSWER WITHIN
on the ANOVA table, how do you calculate the total SS (bottom left cell)? - ANSWER Add
from top to bottom
SS between groups + SS within groups
on the ANOVA table, how do you calculate the df within groups (second column middle
cell)? - ANSWER SSRT + SSE = Total, so you would subtract the total from the SSRT
If given the df and MS between groups, how would you find the SS between on the
ANOVA table? - ANSWER multiply them
How do you find F on the ANOVA table? - ANSWER divide the MS between groups/ MS
within groups
general rules for solving ANOVA table - ANSWER - divide left to right
- add top to bottom
For the within groups category, the degrees of freedom are - ANSWER nt-C
total df- between df
aka total - SSTR
if the total sample size is 15 and the number of groups sampled is 2, what his the within
group degrees of freedom? - ANSWER 13
15-2
total-between
If the within groups category is 13 and the total sample size is 15, what is the between
, groups degrees of freedom? - ANSWER 2
15-13
total-within
Fischer's method - ANSWER uses a T STAT and does NOT get rid of a type I error
Tukeys method - ANSWER does account for Type I error
when would you reject a ONE way null ANOVA hypothesis? - ANSWER when P<0.5
when would you reject a TWO way null ANOVA hypothesis? - ANSWER when P>0.5
Type 1 error - ANSWER rejecting null when it is true
Type 2 error - ANSWER accepting null when it is false
TF: decreasing a type 1 error decreases the likelihood of a type 2 error - ANSWER
FALSE
decreasing the likelihood of one error INCREASES the likelihood of another
when comparing 2 population means, what is not a restriction? - ANSWER increasing
the sample size
- increasing sample size decreases errors
When do you use a Z distribution - ANSWER when sigma (standard deviation) is KNOWN
When do you use a T distribution - ANSWER When sigma (stdev) is UNKNOWN
When do pool the sample variances - ANSWER when you have 2 groups and their
standard deviations are UNKNOWN but assumed to be equal
if I predict that it will rain tomorrow, would the probability that it rains be the null or the
alternate hypothesis? - ANSWER it would be the alternate
what you want to be true is the alternate hypothesis. the goal is to prove the null to be
false in order to prove the alternate true.
A politician claims that the proportion of babies born two weeks early is increasing.
other believe that no more than .5 of all babies are born two weeks early. identify the
hypotheses to test the POLITICIAN's claim. - ANSWER H0 (Null): P<=.5
Ha(Alternate): P>.5
this is an example of a one way test.
it is also a right tail test >
right tail test - ANSWER alternate >
AND CORRECT ANSWERS
What does a one way anova test tell you? - ANSWER it tells you a yes or no answer on
whether one group is different from the other
what does a two way anova test tell you? - ANSWER it conditions groups based on TWO
facors rather than one
when is it appropriate to use a TWO way ANOVA test? - ANSWER when you REJECT the
NULL on a one way
is SSTR between groups or within groups - ANSWER BETWEEN
Is SSE between groups or within groups? - ANSWER WITHIN
on the ANOVA table, how do you calculate the total SS (bottom left cell)? - ANSWER Add
from top to bottom
SS between groups + SS within groups
on the ANOVA table, how do you calculate the df within groups (second column middle
cell)? - ANSWER SSRT + SSE = Total, so you would subtract the total from the SSRT
If given the df and MS between groups, how would you find the SS between on the
ANOVA table? - ANSWER multiply them
How do you find F on the ANOVA table? - ANSWER divide the MS between groups/ MS
within groups
general rules for solving ANOVA table - ANSWER - divide left to right
- add top to bottom
For the within groups category, the degrees of freedom are - ANSWER nt-C
total df- between df
aka total - SSTR
if the total sample size is 15 and the number of groups sampled is 2, what his the within
group degrees of freedom? - ANSWER 13
15-2
total-between
If the within groups category is 13 and the total sample size is 15, what is the between
, groups degrees of freedom? - ANSWER 2
15-13
total-within
Fischer's method - ANSWER uses a T STAT and does NOT get rid of a type I error
Tukeys method - ANSWER does account for Type I error
when would you reject a ONE way null ANOVA hypothesis? - ANSWER when P<0.5
when would you reject a TWO way null ANOVA hypothesis? - ANSWER when P>0.5
Type 1 error - ANSWER rejecting null when it is true
Type 2 error - ANSWER accepting null when it is false
TF: decreasing a type 1 error decreases the likelihood of a type 2 error - ANSWER
FALSE
decreasing the likelihood of one error INCREASES the likelihood of another
when comparing 2 population means, what is not a restriction? - ANSWER increasing
the sample size
- increasing sample size decreases errors
When do you use a Z distribution - ANSWER when sigma (standard deviation) is KNOWN
When do you use a T distribution - ANSWER When sigma (stdev) is UNKNOWN
When do pool the sample variances - ANSWER when you have 2 groups and their
standard deviations are UNKNOWN but assumed to be equal
if I predict that it will rain tomorrow, would the probability that it rains be the null or the
alternate hypothesis? - ANSWER it would be the alternate
what you want to be true is the alternate hypothesis. the goal is to prove the null to be
false in order to prove the alternate true.
A politician claims that the proportion of babies born two weeks early is increasing.
other believe that no more than .5 of all babies are born two weeks early. identify the
hypotheses to test the POLITICIAN's claim. - ANSWER H0 (Null): P<=.5
Ha(Alternate): P>.5
this is an example of a one way test.
it is also a right tail test >
right tail test - ANSWER alternate >
