STAT 701 Assignment #8 (Due by Monday, Nov. 5th)
1 – Exercise Performance and Ipratropium Bromide Aerosol Dose
A study by Ikeda et al., (Thorax, 1996), was designed to determine the does of ipratropium bromide aerosol that improves exercise performance using progressive cycle ergometry in patients with stable chronic obstructive pulmonary disease. The mean age of the 20 male subjects was 69.2 years with a standard deviation of 4.6 years. Among the data collected were the maximum ventilation (VEmax, L/min.) values at maximum achieved exercise for difference ipratropium bromide dosage levels (g).
Data File: VE max IBA
a) Analyze these data to determine if the mean maximum ventilation differs significantly as a function of dose. Summarize your findings. (4 pts.)
b) Use Dunnett’s procedure to compare each dosage level with placebo. Which dosage levels, if any, significantly differ from placebo? (3 pts.)
c) Assuming that the larger VE values are best, what dosage would you recommend? Justify your choice. (3 pts.)
2 – Calcium Intake and Age for Women Between the Ages of 20-88 yrs.
Ilich-Ernst et al. in their paper “Critical Factors for Bone Health in Women across the Age Span: How Important is Muscle Mass?” in Medscape Women’s Health eJournal (2002) investigated dietary intake of calcium among a cross section of 113 healthy women ages 20-88. The researchers formed four age groups as follows: Group A (20 – 45.9 years), Group B (46.0 – 55.9) years, Group C (56.0 – 65.9) years, and Group D (66+ years). Calcium from food intake was measured in mg/day and the results are contained in the file Calcium Intake.JMP.
a) Is there evidence to suggest that calcium intake differs significantly across the age groups? Conduct an appropriate test to answer this question. Be sure to check assumptions required for your analysis. (4 pts.)
b) If there are significant differences, which age groups significantly differ in terms of
there mean calcium content? Also quantify and discuss any significant differences
you find. (4 pts.)
c) Write a short summary of your findings from parts (a) and (b). (2 pts.)
3 – Length of Home Health Visits and Time of Day
The nursing supervisor in a local health department wished to study the influence of time of day on length of home visits by the nursing staff. It was thought that individual differences among the nurses might be large, so the nurse was used as a blocking factor. The nursing supervisor collected the following data:
Length of Home Visit by Time of DayNurse / Early AM / Late AM / Early PM / Late PM
A / 27 / 28 / 30 / 23
B / 31 / 30 / 27 / 20
C / 35 / 38 / 34 / 30
D / 20 / 18 / 20 / 14
Data File: Nurse Visit.
a) Conduct an appropriate test to determine if the mean length of visit is related to the time of day. Summarize your findings. (4 pts.)
b) Conduct multiple comparisons to compare the mean lengths of stay between the different times of the visits. Also examine CI’s for the differences in means. Summarize your findings. (4 pts.)
4 - Tourette's Syndrome and Nicotine Gum
McConville et al. report the effects of chewing one piece of nicotine gum (containing 2 mg of nicotine) on tic frequency in patients whose Tourette's disorder was inadequately controlled by haloperidol. In the study, the number of tics in a 30 minute period was measured at baseline and then each patient was given a piece of nicotine gum. The number of tics observed for the 30 minutes while they were chewing the gum was recorded and then for the two consecutive half hour periods after they spit out the gum.
After eliminating patient effects, can we conclude that the mean number of tics differs among the four conditions? These data are in the file Tourettes.JMP. (6 pts.)
The variables in the data file are:
· Patient – patient ID number
· Time Period –
1 - Base (baseline)
2 - Gum Chew (while chewing gum)
3 - 0 – 30 min (0 – 30 minutes after chewing gum)
4 - 30 – 60 min (30 – 60 minutes after chewing gum)
* Note: Each time period was 30 minutes in length
· Tics/30 min – number of tics during the 30 minute period (response)
a) Conduct an appropriate test to determine if the mean number of tics per 30 minute period is related to the four conditions. Summarize your findings. (4 pts.)
b) Use an appropriate multiple comparison procedure to compare the mean number of tics per 30 minutes across the different time periods. Also examine CI’s for the differences in means. Summarize your findings. (4 pts.)