Download STAT 315 Fall 2003 - University of South Alabama

STAT 315 Fall 2003
Quiz
1. Name two measures of central tendency. ________ _________
2. The unknown values of population parameters are estimated by
appropriate ______ __________ .
3. One of the methods to draw a true representative sample from
population is ___________________________ .
4. One of the tools to draw such a sample is ___________________ .
5. When information is collected on each and every member of the
population, such a survey is called _______ .
6. What measure of dispersion would be appropriate when the outliers are present in the data?
__________________ .
7. Second Quartile is also known as ______________ .
8. A random experiment consists of recording the GPA of a randomly picked student at USA,
what is the sample space ? ________________ .
9. A random experiment consists of surveying some families in a city. The question asked was
“how many vehicles a family owns?” what is the sample space ? ________________________
10.In a random experiment of tossing a 20-faced die, the event E is described as occurrence of a
prime number. Is this event simple or compound ? ________________.
11. The classical approach to assign probability to an event requires that all the events in the
sample space must be equally likely. ( T
/
F).
12. If an experiment is repeatable then the other possible approach to assign probability is
____________________ .
13. Two events in a sample space are mutually exclusive if ___________________ .
14. In an experiment of tossing two coins, probability of atleast one head is .75 then the
probability of the complementary event is ___________________ .
15.Two events in a sample space are independent if ___________________ .
Given two independent events A and B , each with probability p, the probability that
16. Both of them occur together is ___________ .
17. At least one of them occurs is ____________ .
18. None of them occurs is _______________ .
19. A fair coin is tossed three times, the probability of no heads is _______ .
20. The probability of one or more heads is _______________ .
21. A hypergeometric distribution has three parameters namely N, D and n where N is _________
D is __________________ and n is ________________ .
22. A binomial distribution has two parameters n and p , where n is ___________ and p is
_____________ .
23. For a binomial distribution mean is _____________ and variance is _____________ .
24. Value of first
( raw / central ) moment is zero . tick the correct answer.
25. Express variance in terms of raw moments _____________________ .
Following two are bonus questions .The score will be added to your quiz 4 score.
26. Two events are independent then so are their complementary events. ( T / F)
27. Two events are mutually exclusive, so are their complementary events ( T / F)
Let X1 and X2 be two random variables then answer following three questions:
1. The joint probability distribution of X1 and X2 is given by
f(x1, x2) = P( X1 =x1 X2 = x2) (T / F)
2. The marginal probability distribution of X1 is given by
f1(x1) = P( X1 = x1) =
 f (x , x )
x2
1
2
( T / F)
3. Conditional distribution of X1 given X2 = x2 is given by
f( x1 | X2 = x2) =
f ( x1 , x2 )
provided f 2 ( x2 )  0
f 2 ( x2 )
( T / F)
X is a random variable with mean μ and variance σ 2 , answer following two questions
4. The standardized random variable Z has mean 0 and variance 1. ( T / F)
5. If g(X) = aX + b is a new random variable then variance of g(X) is a2 σ 2 . (T / F)
X is a random variable with mean μ and variance σ 2, answer following two questions:
1. The standardized variable z = ____________ (write the formula)
2. Sample mean itself is a random variable (T / F).
3. The sample mean with sample size n has parameters _________ and _________ .
4. The central limit theorem says that irrespective of the population distribution, the sample
mean will be distributed as standard normal whenever sample size is large ( T / F).
5. When we talk about sampling distribution of sample mean, when does t-distribution comes in
the picture?
Type two error is inversely proportional to the distance between null hypothesis and the alternative
hypothesis ( T /
F)
1. To compute the beta value we must know the probability of type one error –alpha.
(T / F)
2. To compute the beta value we must have an alternative specific value of
population parameter. ( T / F)
3. Do the alpha and beta affect each other? ( Yes
/
No)
4. Higher the p-value, stronger the null’s claim. ( T /
F)
Answer the following five questions about ANOVA procedure.
5. ANOVA is a procedure to compare the ( means / variances) of the many
populations .
6. The ANOVA procedure is developed under the assumption that (means /
variances ) of all the populations are equal.
7. Another assumption is that all samples are (dependent /
independent).
8. And it is required that all samples collected should be of equal size ( T / F)
9. The test statistic used in this procedure is ( z-
/ t-
/ F- ).
Quiz 12 ST 315
Answer the following five questions about ANOVA procedure.
1. In the regression equation E (Y )   o  1 X , the response variable is (X /
and the independent variable is ( X
Y)
/ Y)
2. To estimate  0 and  1 , the method of estimation used is ( method of moments /
method of least squares / method of maximum likelihood)
3. All the error terms in the regression equation are independent identically
distributed with distribution ______________________ .
4. The degree of relationship between X and Y is measured by Pearson’s
coefficient of correlation. ( T / F).
5. The sign of (  0 /
 1 ) depends on the sign of coefficient of correlation.