BSTAT Final Exam

One-Way ANOVA Assumptions

1. the populations are normally distributed 2. the population SD's are unknown but assumed equal 3. the samples are selected independently

11. A regression equation is generally used to: a. Predict the value of the dependent variable for a given value of the independent variable b. Predict the value of the independent variable for a given value of the dependent variable c. Measure the strength of the association between two variables d. All of the above

A

15. What type of analysis is used to determine if there is a difference in sales between... a. One way ANOVA b. Two way ANOVA c. Regression analysis d. Correlation analysis e. None of the above answers are correct

A

28. A method of determining if there are differences between... a. The Kruskal-Waillis Test b. The Wilcoxon Rank-Sum test c. The wilcoxon signed rank test d. None of the above

A

3. Which statement is correct about the F distribution? a. The values cannot be negative b. The values cannot be positive c. The values can be negative, zero, or positive d. It is negatively skewed

A

32. Which of the following would be used as a point estimate for the population mean? a. The sample mean b. The test statistic c. The sample standard deviation d. The population mean e. The z value

A

33. Mileage was recorded for a sample of 100 tires. The average tread life was 50,000 miles with a standard deviation of 3,500 miles. What is the best estimate of the average tread life for the population of tires? a. 50,000 b. 3,500 c. (50,000/100) d. (3,500/100) e. None of the above could provide a good estimate

A

34. What kind of distribution is the t distribution? a. Continuous b. Discrete c. Sampling

A

35. How is the t distribution different from the z distribution? a. The t has more variability b. The t is a continuous distribution c. The t has a mean of zero d. The t is a discrete distribution e. Both A and B are differences

A

40. A null hypothesis makes claims about a. Population parameter b. Sample statistic c. Sample mean d. Z-value e. Any of the above

A

43. What is a Type II Error? a. Accepting a false null hypothesis b. Rejecting a false null hypothesis c. Accepting a false alternative hypothesis d. Rejecting a false alternative hypothesis e. Rejecting a true null hypothesis

A

5. In ANOVA, the variation that is explained by the factor is: a. The Variation between the samples b. Te variation within the samples c. The error variation d. The standard error

A

56. For a data set with some variation in the data and an even number of observations, half is greater than a. Median b. Mode c. Mean d. All of the above e. None of the above

A

62. The sum of the deviations from the mean is a. Zero b. The variance c. The standard deviation d. The range e. Unknown

A

68. The weight of the people is a. A continuous random variable b. A discrete random variable c. Interval data d. Ordinal data e. None of the above

A

Covariance

A measure of linear association between two variables. Positive values indicate a positive relationship; negative values indicate a negative relationship

Sample covariance

A measure of the linear relationship between two variables, x and y; a positive value(positive relationship) implies that when one variable is above its means, the other variable is also; a negative value(negative relationship) implies that when one variable is above its mean, the other is below

1. In the analysis of variable procedure (ANOVA) the "factor" might also be called: a. The dependent b. The independent c. The response variable d. The test static

B

27. Statistical methods that do not generally make the assumption... a. Parametric methods b. Nonparametric methods c. Analysis of variance methods d. None of the above

B

29. The mean of the samples means is a. The sample mean b. The population mean c. Unable to determine d. Usually smaller than the population mean e. None of the above

B

36. A test to determine if the mean of a population is greater than 40 resulted in a test statistic of 1.05. The sample size was 10. What was the p-value? a. Less than 0.20 b. Greater than 0.10 c. Greater than 0.20 d. 0.1469 e. None of the above

B

37. Which of the following is true? a. If the results of a test are statistically significant, they must also be practically significant b. The results of a hypothesis test can have statistical significance without practical significance c. The results of a hypothesis test cannot have both statistical significance and practical significance d. None of the above is true

B

38. University officials say that a fee increase will be implemented if more than 75% of the voting student population supports the fee increase. If a sample of students reveals a 95% CI of (0.71,0.83), what conclusion can be drawn based on the interval? a. Conclude that another sample is needed, because this one was not representative b. Conclude it should not be implemented c. Conclude it should be implemented d. This interval does not allow any conclusion to be drawn

B

39. If the confidence interval is too wide to be useful, what can be done? a. Increase the level of confidence b. Increase the sample size c. Increase the variability in the population d. Either A or B would be a good choice e. All of the above would be good choices

B

4. An F test statistic is: a. A standard error b. A ratio of two variances c. The difference between two or more means d. A population parameter

B

41. Using a 0.05 level of significance for a one population test with a sample size of 25, what is the rejection region for a one tailed, upper tail, hypothesis test? a. 1.96 b. 1.711 c. 2.060 d. 2.064

B

46. Based on the Nielsen Ratings, the local CBS affiliates claims its 11:00 PM newscasts reaches more than 41% of the viewing audience in the area. In a sample of 100 viewers, 36% indicated that they watch the late evening news on this location CBS station. What is the null? a. π >0.41 b. π ≤ 0.41 c. π ≤ 0.36 d. π > 0.36 e. π ≥ 0.36

B

47. The power of a hypothesis test is a. Its ability to answer a question about a population parameter b. The probability of rejecting the null hypothesis when the null is fake c. That we can make inferences about a sample mean d. None of the above are correct e. A, B, & C are correct

B

48. During hypothesis testing, the initial assumption about the null hypothesis is a. It is false b. It is true c. It is unknown d. No assumption is made

B

49. When conducting dependent samples, paired data tests, the sample estimate a. One of the sample means b. The mean of the differences c. The population mean d. The sample standard deviation

B

53. What type of variable is the amount of time spent sleeping per day? a. Interval b. Continuous c. Ordinal d. Discrete e. None of the above

B

6. This of the following values would indicate a stronger association base... a. 0 b. -.97 c. .83 d. 100

B

63. What is the relationship between variance and standard deviation? a. Variance is the square root of the standard deviation b. Variance is the square of the standard deviation c. Variance is double the standard deviation d. Variance is half the standard deviation e. There is no relationship between variance and standard deviation

B

67. A listing of all possible outcomes of a random variable along with the corresponding probabilities of occurrences is called a a. Random variable b. Probability distributions c. Population d. Sample e. None of the above

B

71. If we choose a random starting point and then select every fifth invoice in a file, what type of sample is being employed? a. Simple random sampling b. Systematic sampling c. Stratified random sampling d. Cluster sampling e. None of the above

B

73. The difference between a population parameter and a sample statistic is a. At the center of a normal distribution b. Sampling error c. Usually very large d. Usually very small e. None of the above

B

12. Larger values of r^2 imply that: a. The average of the independent variable in high b. Average value of the independent variable is low c. The regression line fits the data well d. The line passes through the origin

C

31. The mean number of travel days per year for sales people employed by hardware distributors needs to be estimated with 95% confidence. For a small pilot study the mean was 150 days with a standard deviation of 14 days. If the population mean is to be estimated within two days, how many salespeople should be sampled? a. 13.72 b. 14 c. 189 d. 150 e. Unable to determine from the information provided

C

42. What type of information is needed to find a p-value? a. Type of test and alpha level b. Alpha level and test statistic c. Type of test and test statistic d. Type of test, alpha level and test statistic

C

45. What is the probability of making a Type II Error if the null hypothesis is actually true? a. Alpha b. 1 c. 0 d. 0.025 e. It is usually 0.05

C

50. A sample of 20 randomly selected students was given a multiple choice test and an essay on the same material and the scores were recorded for both tests for each of the 20 students. The professor was interested in determining which type of test would result in higher scores. This is an example of a. A one sample test of a population proportion b. A test for the differences between two population means c. A dependent samples (paired data, repeated measures) test d. A test of the differences between two population proportions e. None of the above

C

57. For data that has been ordered from smallest to largest data, where is the median located? a. N b. n/2 c. (n+1)/2 d. N + ½ e. N + 2

C

58. The hours worked for a sample of employees are: 6, 0, 10, 14, 8, & 0. What is the median hours worked? a. 12 b. 6 c. 7 d. 8 e. There is no median for this data

C

61. What is the level of measurement needed in order to calculate the variance of a set of data? a. Discrete b. Ordinal c. Interval d. Ratio e. Continuous

C

65. The number of hours per semester worked for a sample of students follows: 139, 136, 131, 136, 147, 130, 135, 138, 139, and 142. What is the mode? a. 136 b. 139 c. 136 and 139 d. 136, 138, and 139 e. None of the above

C

66. If the variance for a sample of hourly wages was computed to be $25, what is the standard deviation? a. $625 b. $25 c. $5 d. $50 e. Cannot be determined from the information provided

C

69. For a normal distribution, the mean plus and minus 2 standard deviations will include about what percentage of observations? a. 50% b. 99.7% c. 95% d. 68% e. All of the observations

C

7. If the coefficient of correlation equals 0.40, then which of the following will... a. There is a strong relationship between the two variables b. 40% of the variation in one variable is explained by the other c. The coefficient of determination is 0.16 d. The coefficient of determination is .40

C

70. What is the area under the normal curve between z=1.00 and z=1.79? a. 0.4633 b. 0.79 c. 0.1220 d. 2.79 e. None of the above

C

8. If all the data for a regression analysis are plotted on a scatter diagram...of estimate would be: a. -1 b. +1 c. 0 d. It cannot be determined from this information

C

10. Which of the following is true about the standard error of estimate? a. It is also called the coefficient of error b. Is it based on squared deviations between the actual Y values and actual X values c. It can be either negative or positive d. It is based on squared deviations between the actual Y values and predicted Y values

D

13. In a simple regression analysis, if the Y intercept is positive, then: a. There is a positive relationship between X and Y b. If X is increased, Y must also increase c. If Y increased, X must also increase d. None of these alternatives is correct

D

2. Regarding the ANOVA procedure; the appropriate situation for making inferences about...pairs of treatment means would be: a. When one way ANOVA design has been used b. When a two way ANOVA design has been used c. When the null hypotheses is has not been rejected d. When the null hypotheses has been rejected

D

30. The standard error is a. The standard deviation of the sample b. The standard deviation of the population c. The standard deviation of the population distribution d. The standard deviation of the sample distribution e. Both A and D are correct

D

44. If the alternative hypothesis states that µ does not equal 4,000, where is the rejection region for the hypothesis test? a. Center of the distribution b. Lower or left tail of the distribution c. Upper or right tail of the distribution d. Both tails of the distribution

D

51. Which of the following is NOT a use of descriptive statistics? a. Organizing b. Summarizing c. Presenting d. Predicting e. All of the above are uses

D

52. Education was measured as Freshman, Sophomore, Junior and Senior. What is the level of measurement? a. Interval b. Ratio c. Nominal d. Ordinal e. Continuous

D

54. What type of variable is the number of auto accidents reported in a given month? a. Interval b. Ordinal c. Continuous d. Discrete e. None of the above

D

55. Age is what level of measurement? a. Nominal b. Ordinal c. Interval d. Ratio e. Continuous

D

59. A disadvantage of using the mean to summarize a set of data is the mean a. Is not unique to a set of data b. Can be used for interval or ratio data c. Is always different from the median d. Can be influenced by extreme values e. Both A and D are disadvantages

D

60. The mean as a measure of central location would be inappropriate for which of the following? a. Ages of adults at a senior citizen center b. Weights of people residing in the state of Georgia c. Number of pages in textbooks on statistics d. Marital status of college students at a particular university e. It would be appropriate for all of the above

D

64. The number of hours per semester worked for a sample of students follows: 139, 136, 131, 136, 147, 130, 135, 138, 139, and 142. What is the range? a. 10 b. 136 and 139 c. 130 and 147 d. 17 e. None of the above

D

72. When dividing a population into groups so that a random sample of the groups can be collected, what type of sample is used? a. Simple random sampling b. Systematic sampling c. Stratified random sampling d. Cluster sampling e. None of the above

D

c. The sales training is useful 23. A large home improvement store interested in the relationship between....and the amount of display space allotted to the fertilizer. The correlation...of 12 weeks was calculated to be .874 using Pearsons correlation coefficient...hypothesis test to determine if there is a positive association between weekly...hypothesis would be? a. B1=b2 b. B1=0 c. B1≠0 d. P=0 e. p≠0

D

F is different because it is positively skewed and non negative F is same because it is continuous

How is F distribution different from z and t? ....Similar?

Multicollinearity

When the independent variables are related to each other so strongly that it becomes difficult to estimate the partial effect of each independent variable on the dependent variable.

9. If the correlation between two variables is close to one, the association is? a. Strong b. Moderate c. Weak d. Nonexistent

a

Scatterplot

a graphed cluster of dots, each of which represents the values of two variables

Two-way ANOVA (Randomized Block Design)

a method used to study the effects of two factors on a response variable(dependent)

correlation coefficient (same for sample CC)

a statistical index of the relationship between two things (from -1 to +1); determines the direction and strength

One-way ANOVA (Completely Randomized Design)

compares population means based on one categorical variable or factor

ANOVA Test

determines if differences exist between the means of 3 or more populations under independent sampling

Repeated measures ANOVA

has at least 1 dependent variable that has more than one observation.

Sum of Squares (SS)

sum of squared deviations from the mean

Error Sum of Squares

the degree of variability that exists even if all population means are the same

Interaction

the impact of one factor depends on the level of the other factor.