ECN 221 exam 2 Question and answers
already passed 2025
We can define outliers as observations at least three standard deviation away
from the mean, i.e. |z| ≥ 3. We can also define outliers as observations that
are more than 1.5 IQR below Q1 or above Q3. True or false: In any data set
there are always at least as many outliers using the z-score definition as there
are using the IQR definition. - correct answer ✔False
True or false: No data set can have more than one observation with a z-value
greater than 10. - correct answer ✔False
One of the assigned readings discussed some of the contributions of
Abraham Wald to statistics. We might think of one of these contributions as
being - correct answer ✔Demonstrating the importance of considering units
that don't end up in our data sets.
You are tasked with finding out about ASU student attitudes about the
upcomming election. You have access to student records and contact
information. You decide to email a survey to a selected group of students and
offer them a gift card for participating in the survey. To choose to whom you
will send the email you have a computer program sort the students
alphabetically by last name and select every 50th name. This is an example
of... - correct answer ✔systematic sampling
A confidence interval is constructed as x ̄± margin of error. - correct answer
✔True
α is known as the confidence level. - correct answer ✔False
already passed 2025
We can define outliers as observations at least three standard deviation away
from the mean, i.e. |z| ≥ 3. We can also define outliers as observations that
are more than 1.5 IQR below Q1 or above Q3. True or false: In any data set
there are always at least as many outliers using the z-score definition as there
are using the IQR definition. - correct answer ✔False
True or false: No data set can have more than one observation with a z-value
greater than 10. - correct answer ✔False
One of the assigned readings discussed some of the contributions of
Abraham Wald to statistics. We might think of one of these contributions as
being - correct answer ✔Demonstrating the importance of considering units
that don't end up in our data sets.
You are tasked with finding out about ASU student attitudes about the
upcomming election. You have access to student records and contact
information. You decide to email a survey to a selected group of students and
offer them a gift card for participating in the survey. To choose to whom you
will send the email you have a computer program sort the students
alphabetically by last name and select every 50th name. This is an example
of... - correct answer ✔systematic sampling
A confidence interval is constructed as x ̄± margin of error. - correct answer
✔True
α is known as the confidence level. - correct answer ✔False
