1.24 Studies where data collected over two or more points in time for the same people are called _____. a. cross-sectional studies b. panel studies c. trend studies d. case studies 1.25 A study is designed to assess the effect of training programs on the skills of new manufacturing employees. Twice a day, the manager counts the number of units produced by the new employees who participated in the training. In this study, the independent variable is the ____. a. training program b. employee s experience level c. number of units produced d. number of days each employee has worked 1.26 A study is designed to assess whether computer training is likely to increase accountants use of computers in their jobs. Two hundred accountants who have participated in a week long computer training session are observed for three months before and after the training to determine how many hours per week they use computers in their jobs. In this study, the dependent variable is the _____. a. week-long computer training course b. number of hours per week that accountants use computers on their jobs. c. observers who record computer use in their office. d. the duration of the study.
1.27 A company psychologist wants to conduct a causal-comparative study to explore the effect of IQ on the self-concept of employees. The psychologist administers a measure of self-concept to a group of 300 employees in three different departments. The employees IQ scores range from 95-135. In this study, the independent variable is the_____. a. company psychologist b. number of employees c. employees experience level d. employees IQ scores 1.28 A study is conducted to test two methods to treat depressed college students. Seventy students, ages 18-22, diagnosed as depressed, are randomly assigned to the two intervention groups. The two interventions consist of a series of weekly meetings and online chat among the members of each group and their counselors. A measure to assess their level of depression is administered to the study s partici pants before and after the intervention. The design of the study is: a. true experimental design. b. counterbalanced design. c. quasi experimental design. d. time series.
BASIC CONCEPTS IN STATISTICS
Identify each as a variable or a constant: 2.1. The number of months in a year.
2.2 The gender of female business students in a study designed to investigate their career aspirations.
2.3. The age when people choose to retire.
2.4. The GMAT scores of the senior business class students.
Identify each variable as continuous or discrete:
2.5. Grade level
2.6. Age
2.7. Height
2.8. Number of children in a family
Identify each as nominal, ordinal, interval, or ratio:
2.9. The TV channel watched the most on Thursday night in four cities.
2.10. The percentage of respondents watching each TV program at 8:00pm on Thursday.
2.11. Ranking of the 5 most important problems in the U.S.A. today.
2.12. List of GMAT scores for the business schools in the county.
2.13. Classification of students by the state where they were born.
2.14. The number of residents in six different states.
2.15. Class rank.
Classify each as descriptive or inferential statistics:
2.16 The mean quality scores of all the plants owned by a company.
2.17. The results of the TV ratings as obtained by A.C. Nielsen for 3000 households with the people-meter (the "black box").
2.18 The number of employees signing up for a new health insurance plan.
2.19 The blood pressure of a group of volunteers given a new experimental drug to lower blood pressure.
Fill in the blanks:
2.20 The most important characteristic of a good sample is that it is _________ of the population.
2.21. A study where numerical information about the total population is gathered by including all members of the population is called a __________.
2.22. The sample's statistics are used to estimate the population's _________.
2.23. When every 20th person is chosen from a group of 1000 people, we obtain a __________ sample.
2.24. A hypothesis that predicts that there is a difference or relationship between variables or groups is called the __________ hypothesis, and is represented by the symbol HA or H1.
2.25. When means from two groups are compared, the null hypothesis states that the difference between the means is _________.
2.26. In order to decide whether the null hypothesis should be rejected or retained, the sample statistic obtained as a result of the statistical calculations is compared to the appropriate __________, found usually in a table in an appendix in statistics books.
2.27. In many statistical tests, degrees of freedom (df) are calculated by subtracting 1 from _______.
Circle the correct answer:
2.28 A biased sample contains a random/systematic error.
2.29 A random sample is always/may not always be representative of the population from which it was selected.
2.30. To analyze data measured on a nominal scale, researchers should use parametric/nonparametric statistics.
2.31. The information gained about the sample is used to generalize to the population and to estimate its values in descriptive/inferential statistics.
2.32. Inferential statistics may/may not include descriptive statistics, such as the mean.
2.33. When we predict which mean is going to be higher, our hypothesis is directional/nondirectional.
2.34. If we reject the null hypothesis at p
2.35. When there is a very small difference between means obtained on a measure at the end of a study, the null hypothesis is likely to be rejected/retained.
2.36. A low correlation is more likely to be statistically significant when the sample size is large/small.
2.37. When the probability level is set prior to the start of the study, it is represented by the letter p/alpha ( ).
2.38. The error made by researchers who retain a null hypothesis when in fact it should be rejected is called Type I/Type II error.
2.39 The hypothesis that always states that the correlation is not significantly different from zero is the null/alternative hypothesis.
2.40. Effect size is used to evaluate the practical/statistical significance of the study.
2.41. When selecting a number of equal-size samples from the same population, the means of the samples are likely to be the same as/different from the population mean.
2.42. The standard error of the means is the standard deviation of the sample means/population means.
2.43. To estimate a population value that is of interest to them, researchers use the effect size/confidence interval.
Circle the best answer:
2.44. Equal distances between the various points on the scale are found in __________.
a. a nominal scale b. an ordinal scale c. both nominal and ordinal scales d. both interval and ratio scales
2.45. Using numbers to represent categories of observations is an example of a(n)______ scale.
a. nominal b. ordinal c. interval d. ratio
2.46. Equal distances between the various points on the scale, as well as an absolute zero, are found in a(n) ____ scale.
a. nominal b. ordinal c. interval d. ratio
2.47. A sampling procedure where every member of the population has an independent and equal chance of being selected is called a _______ sample.
a. systematic b. random c. stratified d. convenience
2.48. A sample that represents proportionally each segment of the population is a ________ sample.
a. random b. systematic c. stratified d. convenient
2.49. When every 15th person is selected from a population of 2000 people, the obtained sample is a __________ sample.
a. stratified b. systematic c. random d. biased
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