For Test Flashcards

1
Q

What is the 5 step framework for linear regression?

A

Examing the data
Formulating the model
Estimating the model
Validating the model
Making predictions

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2
Q

What is multi collinearity?

A

When two variables contain the same information

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3
Q

How do we detect multi collinearity?

A

With the VIF function, >10 means high collinearity

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4
Q

What does r squared imply?

A

How good the prediction is going to be, the model fit to the data
When R squared is higher this indicates better prediction because of a better fit

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5
Q

What do we use to see to validate a model?

A

F stats

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6
Q

What is a naive prediction?

A

A prediction with only intercepts, no other independent vaiables

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7
Q

What is product cannibalization?

A

New product eats up sales of another brand line

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8
Q

What is a confounding variable?

A

A third variable that influences both other variables

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9
Q

How do we get rid of confounding variables?

A

Add them to the regression as a control variable

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10
Q

For what do we use conjoint analysis?

A

When we want to know what separate attributes should be present in a product

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11
Q

What is the full profiles approach in conjoint analysis?

A

All attributes are included in the analysis

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12
Q

What is it called when only a part of the attributes are used in the design

A

Fractional factorial design

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13
Q

What is an orthogonal design of conjoint analysis?

A

Use a limiting amount profile to answer as much as you can

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14
Q

What is a path worth?

A

The worth of a specific product to customers

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15
Q

What are the three rules in deciding on the value of pathworths?

A

Baseline pathworth = 0
Pathworth of insignificant levels = 0
Pathworth of significant levels = coeffients

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16
Q

How is the importance of a partworth defined?

A

The range of the part worths across the levels, this into a percentage of all ranges combined

17
Q

What are the three parameters if the bass model?

A

Innovation propensity p
Market size M
Imitation propensity Q

18
Q

What is immitation propensity

A

How susceptible you are to friends decisions, how much do you imitatie them

19
Q

Innovation propensity what is it?

A

Own preferences of customers

20
Q

What us the difference between n(t) and N(t) in the bass model

A

N is cumulative adoptions

21
Q

What does a higher p mean?

A

More early adopters because of more intrinsic motivation

22
Q

What does higher Q mean

A

More people adapt each time

23
Q

What are criteria of good clusters?

A

Heterogeneity between clusters they need to be different
Homogeneity within clusters you want it to be the same

24
Q

What are the five steps of cluster analysis?

A
  1. Select a distance measure
  2. Select a clustering procedure
  3. Decide the number of clusters
  4. Validate the clustering
  5. Interpret the clusters
25
Does the variance need to be high or low with the variance method?
Small, so low
26
What are the disadvantages of hierarchical clustering?
High complexity Not usable with big data
27
What are the advantages of hierarchical clustering?
Don’t have to know the number of clusters Fairly stable
28
What are good cluster names characteristics?
Accurate, reflecting the features of the cluster Catchy
29
What is STRESS’s definition?
Differences between the observed and predicted distances between brands
30
When is a control variable good?
Influences both the iv and the dv
31
What is the hypothesis of a KS (kolmogorov-Smirnov) test?
The residuals are distributed normally
32
What does the mds use as input for the predictions?
The distances between brands
33
What are the observations of the mds?
Observations are the differences between brands that are collected from the mds survey
34
What are the predictions of the mds?
They are calculated differences like euclidean distance
35
How does the MDS procedure obtain the predictions?
Calculates distances between brands with certain distance measures like Euclidean measure