Aperçu des semaines
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The use of probability models and statistical methods for analyzing data has become
common practice in virtually all scientific disciplines. This course attempts to provide
a comprehensive introduction to those models and methods most likely to be encoun-
tered and used by students in their careers in engineering and the natural sciences.
Although the examples and exercises have been designed with scientists and engi-
neers in mind, most of the methods covered are basic to statistical analyses in many
other disciplines, so that students of business and the social sciences will also profit
from reading the book.
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Test N°1 :
An IT student, working on his thesis, plans a survey to determine the proportion of all computer users who regularly scan flash disks before using them. He decides to interview his classmates in the three classes he is currently enrolled.
a). What is the population of interest?
All computer users who regularly scan flash disks before using them.
b). Do the student’s classmates constitute a simple random sample from the population of interest ?
No
c). What name have we given to the sample that the student collected ?
convenience sampling
d). Do you think that this sample proportion is likely to overestimate , or underestimate the true proportion of all computer users that regularly scan ask disks before using them? Overestimate, because he surveyed just IT students who are expected to use computers more than others.
Test N°2 :
A researcher wishes to estimate the average amount spent per person by visitors to a theme park. He takes a random sample of forty visitors and obtain an average of 28 person.
a.What is the population of interest. All visitors to a theme park
b.What is the parameter of interest. Average amount spent per person
c.Based on this sample, do we know the average amount spent per person by visitors to park ? Explain fully. No, we obtain an estimation of the average
A researcher wishes to estimate the average weight of newborns in south America in the last five years .He takes a random sample of 235 newborns and obtains an average of 3.27 Kilograms.
a). What is the population of interest ? Newborns in south America in the last five years
b).What is the parameter of interest ? Average weight of newborns
c). Based on the sample , do we know the average weight of newborns in South America in the last five years. No, we have just an estimation
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A researcher wishes to estimate the proportion of all adults who own a cell phone. He takes a random sample of 1.572 adults , 1.298 of them own a cell phone, hence 1298 1572 = 0.83
a).What is the population of interest ? All adults who own a cell phone
b).What is the parameter of interest ? Proportion of all adults who own a cell phone.
c).What is the statistic involved? 0.83