TRUE/FALSE: Mark the answers by highlighting T if the statement is true or F if the statement is false.
T F Q1:
The number of individuals in a family is a continuous variable.
T F Q2:John Cortiz is examining the results of a study that covered the entire population. John is examining a census.
T F Q3:If the population distribution is skewed left, the mean will be less than the median, and if the population distribution is skewed right, the mean will exceed the median.
T F Q4:When two events are mutually exclusive, the probability that either event will occur can be found by simply multiplying together their individual probabilities of occurrence. T F Q5
: A random sample of 64 cars passing a check point on a certain highway showed a mean speed of 60 mph. The standard deviation of speeds is known to be 15 mph. In this case 60 mph is a point estimate of the population mean speed on this highway. T F Q6
: According to the Central Limit Theorem, the shape of the sampling distribution of sample mean (given that n ³ 30) will be normal, whether or not the shape of the population is normal. T F Q7
: If the sample size is large (n ³ 30), the standard deviation of the sample mean will equal the population standard deviation for that random variable. T F Q8
: Level of confidence is another name for level of significance. T F Q9
: If we would reject a null hypothesis at the 5% level, we would also reject it at the 1% level.T F Q10
: In a one-way ANOVA, when the null hypothesis is false, the calculated F-ratio would exceed the critical value of F for the chosen significance level.
(Questions 11 to 25 are 1/2 point each)
MULTIPLE CHOICE: Select the correct answer in each of Questions 11 to 25 by highlighting your choice. There is only one correct answer to each question. Multiple selection will be taken as an incorrect answer.
Q11: Populations are studied using samples because of all of the following reasons except
a. it usually takes too much time to study the entire population.
b. management need not be concerned about sampling error.
c. studying the entire population is not cost effective.
d. it may not be possible to identify all the members of the population.
Q12: Which of the following are factors that are important in determining the size of the sample needed in a study?
1. The amount of variation in the population
2. The size of the population
3. The amount of error that can be tolerated
d. 1, 2, and 3
Q13: Arrange the following steps in correct sequence:
1. Begin sampling.
2. Determine the sample size.
3. Establish the sampling frame.
a. 1, 2, 3
b. 2, 1, 3
c. 3, 1, 2
d. 3, 2, 1
Q14: Consider the following two columns that describe different types of data:
1. Qualitative B. Discrete
2. Quantitative C. Ordinal
The correctly paired groupings of the two columns is
a. 1-AB 2-CD
b. 1-AD 2-BC
c. 1-AC 2-BD
d. 1-BC 2-AD Q15
: What area under the standard normal curve falls outside the Z values -1.96 and 1.96?a. 0.05 b. 0.01 c. 0.90
d. 0.10 Q16
: If each of a set of raw scores is transformed into a Z-score, the new distribution will have a standard deviation equal toa. zero.b. one.c. the mean of the original distribution.
d. the standard deviation of the original distribution. Q17
: Which of the following random variables are continuous and which are discrete? 1. Score in a IQ Test 2. number of kittens in a litter 3. number of cars crossing a Traffic Light in one hour
4. the number of rainy days in a month
a. 1, 2 continuous; 3, 4 discreteb. 1, 3, 4 continuous; 2 discrete
c. 4 continuous; 1, 2, 3 discrete
d. 1 continuous; 2, 3, 4 discrete Q18
: A factor that is varied by an experimenter in order to assess its effect is known as a(n):a. dependent variableb. independent variablec. control variable
d. none of the above Q19
: When (for what level of confidence) do we use Z = 1.645, for a two-sided test or confidence interval?a. 90%b. 95%c. 80%
Q20:Given a two-tail test for the population mean, the null hypothesis contains a(n) __________ sign, and the alternative hypothesis contains a(n) ___________ sign.
a. ¹, =
b. =, ³
c. £, =
d. =, ¹
Q21: The appropriate alternative hypothesis for a lower tail test to determine if mean body weight of all the men who have joined a health club is less than 185 pounds would be
a. HA: m ³ 185 lb.
b. HA: m < 185 lb.
c. HA: m = 185 lb.
d. HA: m ¹ 185 lb.
Q22: Which of the following is/are an appropriate null hypothesis for a two-sided test of the difference between two population means?
1. H0: m1 = m2
2. H0: m1 ¹ m2
3. H0: m1 - m2 = 0
d. both 1 and 3
Q23: If the two samples are not independent, their population means can still be compared using the ____________ statistic.
a. paired t
Q24: A linear regression between Y and X produced the following equation for the least squares line:
= -4.3 + 2.1x
Which of the following statements concerning this relationship is true?
a. For every one-unit increase in X, Y increases 4.3 units.
b. For every one-unit increase in X, Y decreases 2.1 units.
c. For every one-unit increase in X, Y decreases 4.3 units.
d. For every one-unit increase in X, Y increases 2.1 units.
Q25: A regression line has been found and the statistician wants to know if the line has a slope. What is the appropriate null hypothesis to test?
a. H0: b1 = 0.
b. H0: b1 > 0.
c. H0: b1 < 0.
d. H0: b1 ¹ 0.