**Homework 1**

Work on the following problem set and show your works within the document. Use SPSS as much as possible.

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*Chapter 1*

- What types of activities other than “calculations” and “math” are associated with the practice of statistics?
- Define the term measurement.
- List the three main measurement scales addressed in this chapter.
- What type of measurement assigns a name to each observation?
- What type of measurement is based on categories that can be put in rank order?
- What type of measurement assigns a numerical value that permits for meaningful mathematical operations for each observation?
- What does GIGO stand for?
- Provide synonyms for categorical data.
- Provide synonyms for quantitative data.
- What is the difference between imprecision and bias
- How is imprecision quantified?

*Chapter 2*

- Controlled-release morphine in patients with chronic cancer pain. Warfield reviewed 10 studies comparing the effectiveness of controlled-release and immediate-release morphine in cancer patients with chronic pain. The studies that were reviewed were double blinded. How would you double blind such studies?
- What is the general goal of a statistical survey?
- What is the general goal of a comparative statistical study?
- What is the key distinction between experimental studies and observational studies?
- Campus survey. A researcher conducts a survey to learn about the sexual behavior of college students on a particular campus. A list of the undergraduates at the university is used to select participants. The investigator sends out 500 surveys but only 136 are returned.
- Consider how the low response rate could bias the results of this study.

- Speculate on potential limitations in the quality of information the researcher will receive on questionnaires that are returned.
- A study seeks to determine the effect of postmenopausal hormone use on mortality. What is the explanatory variable in this study? What is the response variable?
- MRFIT. The MRFIT study discussed in an earlier illustrative example studied 12,866 high-risk men between 35 and 57 years of age. Approximately half the study subjects were randomly assigned to a special care group; the other half received their usual source of care. Death from coronary disease was monitored over the next seven or so years. Outline this study’s design in schematic form.
- Five-City Project. The Stanford Five-City Project is a comprehensive community health education study of five moderately sized Northern California towns. Multiple-risk factor intervention strategies were randomly applied to two of the communities. The other three cities served as controls. Outline the design of this study in schematic form.

By applying factors in combination, experiments can study more than one factor at a time.

**Homework 2**

Work on the following problem set and show your works within the document. Use SPSS to answer the questions.

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**Chapter 3**

- Suppose the following table is gathered for a new study investigating childhood asthma. What is the average age at interview?

Age at Interview | Asthma? 0=No 1=Yes | |

18 | 0 | |

16 | 0 | |

16 | 1 | |

17 | 1 | |

14 | 1 | |

13 | 1 | |

15 | 0 | |

16 | 1 | |

19 | 1 | |

12 | 0 | |

16 | 0 | |

13 | 1 | |

13 | 1 | |

18 | 1 | |

13 | 0 | |

- Suppose a hospital is given a grant of 1.5 million dollars from the federal government for improvements in care. The managers at the hospital have to determine which departments receive what share of the grant. The following table is a proposed budgetary allocation for each of the main 4 departments at the hospital.

Department |
Proposed Share of Grant |

Surgery | $1,020,000.00 |

Emergency | $255,000.00 |

Pediatrics | $150,000.00 |

Pharmacy | $75,000.00 |

- What proportion of the funding will potentially go to the pediatrics department?
- What proportion of funding will go to all departments other than surgery?

- Suppose the following indexed scores represent performance on a new survey meant to understand an individual’s level of depression. Suppose a score of above 20 represents a depressed individual based on the survey design.

Score |

13.5 |

15.7 |

14.3 |

16.7 |

21.2 |

20.7 |

22.3 |

17.4 |

16.8 |

12.4 |

- What is the relative frequency of those individuals that represent depressed individuals?
- What is the median score for the depression scale in this group of individuals?

- The following values illustrate the annual incomes among a group of households in a particular community.
**What is the mean of the distribution?**

$62,000.00

$84,000.00

$72,000.00

$187,000.00

$295,000.00

$32,000.00

$48,000.00

$64,000.00

$98,000.00

$92,000.00

- Suppose that six individuals are interested in taking part in a study relating BMI to a number of health outcomes. The following 6 numbers represent the individuals’ BMI (kg/m
^{2}). Suppose that a BMI above 30 is considered obese.**What is the relative frequency of obesity in this group?**

25.78

21.06

36.54

29.51

18.96

34.05

**Chapter 4**

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- Researchers are interested in monitoring the CD4 cell counts in a group of HIV positive patients treated with a new anti-retroviral medication. Suppose the following table represents the cd4 counts for a particular patient at various follow-up days in the study. Calculate the mean and standard deviation CD4 counts for the patient under investigation.

CD4 Count (cells/mm^{3}) |
Study Day |

438 | 1 |

421 | 2 |

419 | 7 |

418 | 14 |

411 | 30 |

409 | 60 |

398 | 90 |

- The following table represents the scores on the Mini-Mental State Examination (MMSE) for patients enrolled in a study at an Alzheimer’s disease institute.

Patient | MMSE Score |

A | 21 |

B | 19 |

C | 18 |

D | 22 |

E | 17 |

F | 18 |

G | 22 |

- Calculate the variance and standard deviation for the data

- Calculate the IQR for the performances on the MMSE presented above

- The following data is the annual income (in $1,000s of U.S. dollars) taken from nine randomly chosen students in the CBU MPH program: 37 102 34 12 111 56 72 17 33
- Calculate the sample mean income
- Calculate the sample median income
- Calculate the sample standard deviation of these incomes
- What population could this sample represent?
- Which would change by a larger amount—the mean or median—if the 34 were replaced by 17, and the 12 replaced by a 31?

- The following data shows birthweights (oz) from seven consecutive deliveries at the Loma Linda Hospital in April 2007: 121 138 32 100 58 64 146
- Calculate the sample mean birthweight
- Calculate the sample median birthweight
- Calculate the sample standard deviation of these birthweights
- What population could this sample represent?
- Suppose this is a representative sample of births in a given year at Loma Linda Hospital. Suppose, instead of a sample of seven values, we have a sample of 100 birthweights. How should the mean, median, and standard deviation of this sample compare to the same statistics for the sample of seven birthweights?