Fundamentals of Biostatistics
8th Edition
ISBN: 9781305268920
Author: Bernard Rosner
Publisher: Cengage Learning
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Textbook Question
Chapter 7, Problem 97P
An experiment was performed to assess the efficacy of an eye drop in preventing “dry eye.” A principal objective measure used to assess efficacy is the tear breakup time (TBUT),
which is reduced in people with dry eye and which the researchers hope will be increased after use of the eye drop.
In the actual study, participants will be randomized to either active drug or placebo, based on a fairly large sample size. However, a pilot study was first performed based on 14 participants. Under protocol A, the participants had their TBUT measured at baseline and were then instructed to not blink their eyes for 3 seconds, after which time the placebo eye drop was instilled. The TBUT was measured again immediately after instillation as well as at 5, 10, and 15 minutes postinstillation, during which time the study participants were in a controlled-chamber environment with low humidity to exacerbate symptoms of dry eye. On 2 other days participants received protocols B and C. Protocol B was identical to protocol A except that participants were told not to blink for 6 seconds prior to drop instillation. Protocol C was identical to protocol A except that participants were told not to blink their eyes for 10 seconds prior to drop instillation. Note that the same participants were used for each protocol and that for each protocol data are available for each of two eyes. Also, for each eye, two replicate measurements were provided.
The data are available in TEAR.DAT with documentation in TEAR.DOC at www.cengagebrain.com. For each protocol, TBUT (in seconds) was measured (1) at baseline (before drop instillation), (2) immediately after drop instillation, (3) 5 minutes after instillation, (4) 10 minutes after instillation, and (5) 15 minutes after instillation.
The standard protocol used in previous clinical studies of TBUT is a 6-second nonblink interval (protocol B). All the following questions concern protocol B data. For this purpose, average TBUT over two replicates and over both eyes to find a summary value for each time period for each participant.
Does the effect of the placebo eye drop change over time after drop instillation? (Hint: Compare mean TBUT at 5, 10, and 15 minutes postinstillation vs. mean TBUT immediately after drop instillation.)
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Chapter 7 Solutions
Fundamentals of Biostatistics
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Ch. 7 - The mean serum-creatinine level measured in 12...Ch. 7 - The mean serum-creatinine level measured in 12...Ch. 7 - The mean serum-creatinine level measured in 1 2...Ch. 7 - The mean serum-creatinine level measured in 12...Ch. 7 - The mean serum-creatinine level measured in 12...Ch. 7 - The mean serumcreatinine level measured in 12...Ch. 7 - The mean serumcreatinine level measured in 12...Ch. 7 - Plasma-glucose levels are used to determine the...Ch. 7 - Plasma-glucose levels are used to determine the...Ch. 7 - Plasma-glucose levels are used to determine the...Ch. 7 - Suppose the incidence rate of myocardial...Ch. 7 - Suppose the incidence rate of myocardial...Ch. 7 - Suppose the incidence rate of myocardial...Ch. 7 - Suppose the incidence rate of myocardial...Ch. 7 - Suppose the incidence rate of myocardial...Ch. 7 - Suppose the annual incidence of asthma in the...Ch. 7 - Prob. 18PCh. 7 - Suppose the annual incidence of asthma in the...Ch. 7 - Prob. 20PCh. 7 - Ribosomal 5S RNA can be represented as a sequence...Ch. 7 - Ribosomal 5S RNA can be represented as a sequence...Ch. 7 - Ribosomal 5S RNA can be represented as a sequence...Ch. 7 - Ribosomal 5S RNA can be represented as a sequence...Ch. 7 - Ribosomal 5S RNA can be represented as a sequence...Ch. 7 - Suppose we identify 50 women 50 to 54 years of age...Ch. 7 - The drug erythromycin has been proposed to...Ch. 7 - A pilot study of a new antihypertensive agent is...Ch. 7 - A pilot study of a new antihypertensive agent is...Ch. 7 - The proportion of deaths due to lung cancer in...Ch. 7 - The proportion of deaths due to lung cancer in...Ch. 7 - The proportion of deaths due to lung cancer in...Ch. 7 - The proportion of deaths due to lung cancer in...Ch. 7 - The proportion of deaths due to lung cancer in...Ch. 7 - Iron-deficiency anemia is an important nutritional...Ch. 7 - Iron-deficiency anemia is an important nutritional...Ch. 7 - Iron-deficiency anemia is an important nutritional...Ch. 7 - Iron-deficiency anemia is an important nutritional...Ch. 7 - Iron-deficiency anemia is an important nutritional...Ch. 7 - Iron-deficiency anemia is an important nutritional...Ch. 7 - Iron-deficiency anemia is an important nutritional...Ch. 7 - Iron-deficiency anemia is an important nutritional...Ch. 7 - Suppose a new test is proposed to identify...Ch. 7 - Suppose a new test is proposed to identify...Ch. 7 - Suppose a new test is proposed to identify...Ch. 7 - Suppose a new test is proposed to identify...Ch. 7 - Suppose a new test is proposed to identify...Ch. 7 - The mortality experience of 8146 male employees of...Ch. 7 - The mortality experience of 8146 male employees of...Ch. 7 - The mortality experience of 8146 male employees of...Ch. 7 - The mortality experience of 8146 male employees of...Ch. 7 - Researchers have reported that the incidence rate...Ch. 7 - Researchers have reported that the incidence rate...Ch. 7 - Researchers have reported that the incidence rate...Ch. 7 - Researchers have reported that the incidence rate...Ch. 7 - Left ventricular mass (LVM) is an important risk...Ch. 7 - Left ventricular mass (LVM) is an important risk...Ch. 7 - Left ventricular mass (LVM) is an important risk...Ch. 7 - Left ventricular mass (LVM) is an important risk...Ch. 7 - Prob. 60PCh. 7 - Previous studies have shown that supplementing the...Ch. 7 - Prob. 62PCh. 7 - Prob. 63PCh. 7 - Previous studies have shown that supplementing the...Ch. 7 - Prob. 65PCh. 7 - Prob. 66PCh. 7 - Refer to Data Set NIFED.DAT at...Ch. 7 - The combination of photochemotherapy with oral...Ch. 7 - The combination of photochemotherapy with oral...Ch. 7 - The combination of photochemotherapy with oral...Ch. 7 - Prob. 72PCh. 7 - Breast cancer is strongly influenced by a womans...Ch. 7 - Prob. 74PCh. 7 - An investigator wants to test a new eye drop that...Ch. 7 - Prob. 76PCh. 7 - Table 7.10 gives the itching scores reported by...Ch. 7 - Table 7.10 gives the itching scores reported by...Ch. 7 - Table 7.10 gives the itching scores reported by...Ch. 7 - Table 7.10 gives the itching scores reported by...Ch. 7 - Prob. 81PCh. 7 - Prob. 82PCh. 7 - Concurrent sexual partnerships are widely believed...Ch. 7 - Prob. 84PCh. 7 - Prob. 85PCh. 7 - Prob. 86PCh. 7 - Consider the birthweight data in Example 7.2. 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Now...Ch. 7 - Prob. 89PCh. 7 - A screening program for neuroblastoma (a type of...Ch. 7 - A screening program for neuroblastoma (a type of...Ch. 7 - Prob. 92PCh. 7 - Prob. 93PCh. 7 - Prob. 94PCh. 7 - Prob. 95PCh. 7 - Prob. 96PCh. 7 - An experiment was performed to assess the efficacy...Ch. 7 - Medical errors are common in hospitals throughout...Ch. 7 - Prob. 99PCh. 7 - Prob. 100PCh. 7 - Prob. 101PCh. 7 - Prob. 102PCh. 7 - Prob. 103PCh. 7 - Prob. 104PCh. 7 - Osteoporosis is an important cause of morbidity in...Ch. 7 - Osteoporosis is an important cause of morbidity in...Ch. 7 - Osteoporosis is an important cause of morbidity in...Ch. 7 - Prob. 108PCh. 7 - Prob. 109PCh. 7 - Prob. 110PCh. 7 - Prob. 111PCh. 7 - Prob. 112PCh. 7 - Prob. 113PCh. 7 - A study was conducted in Sweden to relate the age...Ch. 7 - A study was conducted in Sweden to relate the age...Ch. 7 - A study was conducted in Sweden to relate the age...Ch. 7 - Prob. 117PCh. 7 - Prob. 118PCh. 7 - Prob. 119PCh. 7 - Prob. 120PCh. 7 - Prob. 121P
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