questions exam 3 Flashcards
When does the obtained value equals 0?
The obtained chi-square value would equal 0, in case the expected and the observed values are identical
Example when the Obtained value equals 0
A bookstore owner has a sale on average a 100 books per day. His inventory is composed of 30% Math books, 50% English Literature, 10% French and 10% Spanish Language books. At the end of the day, if the books store sells 10 Spanish books, 10 French books, 30 Math books, and 50 English literature books, then the obtained Chi-Square value would be equal to 0.
How does linear regression differ from analysis variance?
LInear regression is used to explore if one variable predicts another, while analysis of variance examines differences between group mean, not prediction.
how will you use chi square in your career?
I will also use the Chi-square to ensure that appropriate amount, frequency, and duration of treatment is distributed to patients in accordance with accepted standards of practice.
When is an analysis of variance a more appropriate use of a statistical technique than a test between a pair of means?
Both methods look at differences between means, but ANOVA is better when there are more than 2 means compared. ANOVA assumes that the groups are independent of one another.
What does the concept of correlation plays in regression?
Regression equation defines the points and the line that are closest to the actual scores. And the line drawn based on the values in the regression equation is known as the regression line. Regression is used for our knowledge of relationships between variables to predict the value of one variable from another. Basically, the data on a past event is collected and then applied to a future event based off one known variable.
In what situation might you want to use multiple regression?
When additional variables are each bringing a unique contribution to understanding the dependant variable, by highlighting differences in the predicted variable that were not explained by the first predictor.
All variables predict the outcome better than anyone of them would have done alone
Give an example of a multiple regression
Prediction of college graduates employment rates in professional life Y1=employment rates X1=average GPA X2=Gender X3=Race X4=no of internship taken
F Ration/ANOVA. What is the F-Ratio of?
It is the ratio of Variability between groups to variability within groups
Why does each ANOVA has 2 sets of DF?
DF for numerator (k-1) and DF for denomiantor (n-k)
One for the between group and one for the within group
ANOVA shows the significant difference between groups. Can ANOVA tell you which group is causing the difference?
No
True or False. ANOVA tests can be directional or non directional
False, they are directional
What is Sum of Squares computed for?
For each source of variability)
Between Groups
Within Groups
Total
Understand ANOVA short hand
Ex: F (2,27)=8.8, p<.05 indicates that the probability is less than 5% on any one test of the NH that the average scores of each group outcome is due to chance=significant difference between the set of scores
What does the chi square on sample test assess?
That any set of occurence does not happen by chance in a frequency
