Exam (elaborations)
STA 270 CHAPTER 1 TEST QUESTIONS AND ANSWERS
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STA 270 CHAPTER 1 TEST QUESTIONS AND ANSWERS...
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What are the two major types of statistics? - ANSWER Descriptive,Inferential
Descriptive Statistics consists of organizing and summarizing information
collected - ANSWER Descriptive Statistics
uses methods that generalize results obtained from a sample to the
population and measure the reliability of the results - ANSWER
inferential statistics
Observational study - ANSWER When researchers simply observe
characteristics and take measurements, as in a sample survey.
Designed experiment - ANSWER researchers impose treatments and
controls and then observe characteristics and take measurements.
Observational studies can reveal - ANSWER only reveal association
designed experiments can help establish - ANSWER causation
A nationwide survey of 1000 adults found that 50% of respondents
favored a plan to break up the 12 megabanks, which then controlled
about 69% of the banking industry. Complete parts (a) and (b) below.
a. Identify the population and sample for this study.
b. Is the percentage provided a descriptive statistic or an inferential
statistic? Explain your answer. - ANSWER (a) The population is all
adults in the country. The sample is the 1000 adults surveyed.
(b) The percentage is a descriptive statistic, since it summarizes
information about how much of the sample favors breaking up the
megabanks.
State whether the investigation in question is an observational study or a
designed experiment. Justify your answer.
, In the article "One's Sex, Sleep, and Posttraumatic Stress Disorder", I.
Kobayashi et al. study the relationship between one's sex, sleep
patterns, and posttraumatic stress disorder (PTSD) after trauma
exposure. The authors report that women have a higher lifetime
prevalence of PTSD as well as a greater risk of developing PTSD
following trauma exposure. Relationships between sleep and physical
health have been documented in a number of studies, and the authors
explore the possibility that disruptive sleep habits are common among
people with PTSD and also a possible risk factor for the development of
PTSD. A questionnaire of men and women with and without PTSD
produced data on their sleep habits. - ANSWER The study is
observational because the researchers did not impose any conditions on
the subjects before collecting the data.
State whether the investigation in question is an observational study or a
designed experiment. Justify your answer.
In a paper in a medical journal, researchers reported the results of a
study of methods for treating patients who had advanced heart failure
due to ischemic or nonischemic cardiomyopathies. A total of 1590
patients were randomly assigned in a 2:1:1 ratio to receive optimal
pharmacologic therapy alone or in combination with either a pacemaker
or a pacemaker-defibrillator combination. The patients were then
observed until they died or were hospitalized for any cause. - ANSWER
The study is a designed experiment because the researchers controlled
the treatment of the subjects.
A report stated that "52% of people between the ages of 18 and 39 favor
raising the minimum wage. "The 52% percentage of 52% was computed
from sample data. Complete parts (a) through (d) below.
a. Identify the population under consideration. - ANSWER all people
between the ages of 18 and 39.
A report stated that "52% of people between the ages of 18 and 39 favor
raising the minimum wage. "The 52% percentage of 52% was computed
from sample data. Complete parts (a) through (d) below.
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