1.27) CT scanning for lung cancer. A new type of screening for

lung cancer, computed tomography (CT), has been devel-

oped. Medical researchers believe that CT scans are more

sensitive than regular X-rays in pinpointing small tumors.

viot The H. Lee Moffitt Cancer Center at the University of

South Florida conducted a clinical trial of 50,000 smokers

nationwide to compare the effectiveness of CT scans with

mibi X-rays for detecting lung cancer. (Todays' Tomorrows, Fall

2002.) Each participating smoker was randomly assigned to

one of two screening methods, CT or chest X-ray, and his or

her progress tracked over time. The age at which the scan-

bus ning method first detects a tumor is the variable of interest.

a. Identify the data collection method used by the cancer

om to researchers.

researchers.prica si gaiverhoq ni bi of stsb

nib. Identify the experimental units of the study. 21

c. Identify the type (quantitative or qualitative) of the

variable measured. iclaxe fyb

x fybuja leofaitsta leit

d. Identify the population and sample.

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e. What is the inference that will ultimately be drawn from

the clinical trial?