STT FINAL EXAM – QUESTIONS & CORRECT SOLUTIONS
In the simple regression model, y+21-5x if the coefficent of determination
(R^2) is .81, we can say that the coefficient of correlation(r) between y and x
is .90. Right Ans - False
In a standard normal distribution, if the area under curve to the right of a z-
value is .10, then the are to the left of the same z-value is .10. Right Ans -
True
The coefficient of determination (R^2) is the proportion of variability of the
dependent variable (y) accounted for or explained by the independent
variable (x). Right Ans - True
In a simple regression the coefficient of correlation (r) is the square root of
the coefficient of determination (R^2). Right Ans - False, R^2 is an absolute
value. Therefore, r could be positive or negative.
The list of all elementary events for an experiment is called the sample space.
Right Ans - True
If the occurance of one event does not affect the occurance of another event,
then the two events are mutually exclusive. Right Ans - False
If the occurence of one event precludes the occurence of another event, then
the two events are independent. Right Ans - False
Given two events, A and B, if the probability of A is .6 and the probability of B
is .4, and the joint probability of A and B is .24, then the two events are
independent. Right Ans - True
Bayes' Rule is an extension of the law of conditional probabilities to allow
revision of original probabilities with new information. Right Ans - True
Z-score Right Ans - number of standard deviations that a value is from the
mean.
In the simple regression model, y+21-5x if the coefficent of determination
(R^2) is .81, we can say that the coefficient of correlation(r) between y and x
is .90. Right Ans - False
In a standard normal distribution, if the area under curve to the right of a z-
value is .10, then the are to the left of the same z-value is .10. Right Ans -
True
The coefficient of determination (R^2) is the proportion of variability of the
dependent variable (y) accounted for or explained by the independent
variable (x). Right Ans - True
In a simple regression the coefficient of correlation (r) is the square root of
the coefficient of determination (R^2). Right Ans - False, R^2 is an absolute
value. Therefore, r could be positive or negative.
The list of all elementary events for an experiment is called the sample space.
Right Ans - True
If the occurance of one event does not affect the occurance of another event,
then the two events are mutually exclusive. Right Ans - False
If the occurence of one event precludes the occurence of another event, then
the two events are independent. Right Ans - False
Given two events, A and B, if the probability of A is .6 and the probability of B
is .4, and the joint probability of A and B is .24, then the two events are
independent. Right Ans - True
Bayes' Rule is an extension of the law of conditional probabilities to allow
revision of original probabilities with new information. Right Ans - True
Z-score Right Ans - number of standard deviations that a value is from the
mean.
