ISYE 6414 - All Units 4 Exam Questions With Correct Verified Answers A+ Graded
6 keer bekeken 0 keer verkocht
Vak
ISYE 6414
Instelling
ISYE 6414
response (dependent) variables - ANS one particular variable that we are interested in understanding or modeling (y)
predicting or explanatory (independent) variables - ANS a set of other variables that might be useful in predicting or modeling the response variable (x1, x2)
What kind of ...
,response (dependent) variables - ANS one particular variable that we
are interested in understanding or modeling (y)
predicting or explanatory (independent) variables - ANS a set of
other variables that might be useful in predicting or modeling the
response variable (x1, x2)
What kind of variable is a response variable and why? - ANS
K
random, because it varies with changes in the predictor/s along with
other random changes.
C
What kind of variable is a predicting variable and why? - ANS fixed,
LO
because it does not change with the response but it is fixed before the
response is measured.
linear relationship - ANS a simple deterministic relationship between
YC
2 factors, x and y
what are three things that a regression analysis is used for? - ANS 1.
Prediction of the response variable, 2. Modeling the relationship
D
between the response and explanatory variables, 3. Testing
hypotheses of association relationships
U
B0 = ? - ANS intercept
ST
B1 = ? - ANS slope
for our linear model where: Y = B0 + B1 + EPSILON (E), what does
the epsilon represent? - ANS deviance of the data from the linear
model (error term)
,what are the 4 assumptions of linear regression? - ANS
Linearity/Mean Zero, Constant Variance, Independence, Normality
Linearity/Mean zero assumption - ANS Means that the expected
value (deviances) of errors is zero. This leads to difficulties in
estimating B0 and means that our model does not include a necessary
systematic component
K
Constant variance assumption - ANS Means that it cannot be true
that the model is more accurate for some parts of the population, and
C
less accurate for other parts of the populations. This can result in less
accurate parameters and poorly-calibrated prediction intervals.
LO
Assumption of Independence - ANS Means that the deviances, or in
fact the response variables ys, are independently drawn from the
data-generating process. (this most often occurs in time series data)
YC
This can result in very misleading assessments of the strength of
regression.
Normality assumption - ANS This is needed if we want to do any
D
confidence or prediction intervals, or hypothesis test, which we usually
do. If this assumption is violated, hypothesis test and confidence and
U
prediction intervals and be very misleading.
ST
what are the 3 parameters we estimated in regression? - ANS B0,
B1, sigma squared (variance of the one pop.)
What do we mean by model parameters in statistics? - ANS Model
parameters are unknown quantities, and they stay unknown
regardless how much data are observed. We estimate those
parameters given the model assumptions and the data, but through
, estimation, we're not identifying the true parameters. We're just
estimating approximations of those parameters.
What is the estimated sampling distribution of s^2? - ANS chi-square
with n-1 DF
Why do we lose 1 DF for s^2? - ANS we replace mu with zbar
K
what is the relationship between s^2 and sigma^2? - ANS S^2
estimates sigma^2
C
What is the estimated sampling distribution of sigma^2? - ANS
LO
chi-square with n-2 DF (~ equivalent to MSE)
Why do we lose 2 DF for sigma^2? - ANS we replaced two
parameters, B0 and B1
YC
In SLR, we are interested in the behavior of which parameter? - ANS
B1
D
If we have a positive value for B1,.... - ANS then that's consistent
with a direct relationship between the predicting variable x and the
U
response variable y.
ST
If we have a negative value for B1,.... - ANS is consistent with an
inverse relationship between x and y
When B1 is close to zero... - ANS we interpret that there is not a
significant association between predicting variables, between the
predicting variable x, and the response variable y.
Voordelen van het kopen van samenvattingen bij Stuvia op een rij:
Verzekerd van kwaliteit door reviews
Stuvia-klanten hebben meer dan 700.000 samenvattingen beoordeeld. Zo weet je zeker dat je de beste documenten koopt!
Snel en makkelijk kopen
Je betaalt supersnel en eenmalig met iDeal, creditcard of Stuvia-tegoed voor de samenvatting. Zonder lidmaatschap.
Focus op de essentie
Samenvattingen worden geschreven voor en door anderen. Daarom zijn de samenvattingen altijd betrouwbaar en actueel. Zo kom je snel tot de kern!
Veelgestelde vragen
Wat krijg ik als ik dit document koop?
Je krijgt een PDF, die direct beschikbaar is na je aankoop. Het gekochte document is altijd, overal en oneindig toegankelijk via je profiel.
Tevredenheidsgarantie: hoe werkt dat?
Onze tevredenheidsgarantie zorgt ervoor dat je altijd een studiedocument vindt dat goed bij je past. Je vult een formulier in en onze klantenservice regelt de rest.
Van wie koop ik deze samenvatting?
Stuvia is een marktplaats, je koop dit document dus niet van ons, maar van verkoper Studyclock. Stuvia faciliteert de betaling aan de verkoper.
Zit ik meteen vast aan een abonnement?
Nee, je koopt alleen deze samenvatting voor €15,23. Je zit daarna nergens aan vast.
