ECN 221 Questions and Answers with Verified Solutions | Latest 2026
Update
Q: rejection rule for simple lin reg
Answer:
p is less than alpha, or f is greater than f (is based on an
Fdistribution with1 degree of freedom in the numerator and n-2 degrees of freedom
in the
denominator)
Q: what is a confidence interval
Answer:
an interval estimate of the mean value of y for a given value of
x.
Q: what is the prediction interval used for
Answer:
used whenever we want to predict an individual
value of y for a new observation corresponding to a given value of x.
,ECN 221 Questions and Answers with Verified Solutions | Latest 2026
Update
Q: relationship between the margin of error and the prediction interval
Answer:
the margin of error is
larger than the prediction interval
Q: difference between a prediction interval in simple lin reg and a confidence
interval eqn
Answer:
add
1+ under the radical for a predicition
Q: each b1, b2, b3...in multi lin reg
Answer:
the amount change in the corresponding y when x1
increases or decreases by 1 unit, holding all else constant.
,ECN 221 Questions and Answers with Verified Solutions | Latest 2026
Update
Q: what does the adjusted multiple coefficient of determination account for
Answer:
when statistically
insignificant variables are added to the equation(SSE gets smaller, to SSR/SST gets
bigger), they
cause R2 to be bigger than it needs to be. thus you need something to adjust for that.
Q: the variance explained
Answer:
R^2
Q: what does the interval estimation tell you
Answer:
How sure are you that this value exists between
these two values
, ECN 221 Questions and Answers with Verified Solutions | Latest 2026
Update
Q: can you calculate the margin of error before you take a sample?
Answer:
yes
Q: 538.org
Answer:
Nate Silver
Q: the question the created the t-table "what if I have less than a lot for my sample?
Answer:
"
Q: what critical t values are a little higher than...
Answer:
the z score
Update
Q: rejection rule for simple lin reg
Answer:
p is less than alpha, or f is greater than f (is based on an
Fdistribution with1 degree of freedom in the numerator and n-2 degrees of freedom
in the
denominator)
Q: what is a confidence interval
Answer:
an interval estimate of the mean value of y for a given value of
x.
Q: what is the prediction interval used for
Answer:
used whenever we want to predict an individual
value of y for a new observation corresponding to a given value of x.
,ECN 221 Questions and Answers with Verified Solutions | Latest 2026
Update
Q: relationship between the margin of error and the prediction interval
Answer:
the margin of error is
larger than the prediction interval
Q: difference between a prediction interval in simple lin reg and a confidence
interval eqn
Answer:
add
1+ under the radical for a predicition
Q: each b1, b2, b3...in multi lin reg
Answer:
the amount change in the corresponding y when x1
increases or decreases by 1 unit, holding all else constant.
,ECN 221 Questions and Answers with Verified Solutions | Latest 2026
Update
Q: what does the adjusted multiple coefficient of determination account for
Answer:
when statistically
insignificant variables are added to the equation(SSE gets smaller, to SSR/SST gets
bigger), they
cause R2 to be bigger than it needs to be. thus you need something to adjust for that.
Q: the variance explained
Answer:
R^2
Q: what does the interval estimation tell you
Answer:
How sure are you that this value exists between
these two values
, ECN 221 Questions and Answers with Verified Solutions | Latest 2026
Update
Q: can you calculate the margin of error before you take a sample?
Answer:
yes
Q: 538.org
Answer:
Nate Silver
Q: the question the created the t-table "what if I have less than a lot for my sample?
Answer:
"
Q: what critical t values are a little higher than...
Answer:
the z score
