Statistics IX - Random Stuff Flashcards Preview

Mei:CogSci Semester 2 > Statistics IX - Random Stuff > Flashcards

Flashcards in Statistics IX - Random Stuff Deck (13):
1

How to calculate the geometric mean?

multiply all values, then n-root it!

2

What does wikipedia say about PCA?

PCA is the simplest of the true eigenvector-based multivariate analyses. Often, its operation can be thought of as revealing the internal structure of the data in a way that best explains the variance in the data. If a multivariate dataset is visualised as a set of coordinates in a high-dimensional data space (1 axis per variable), PCA can supply the user with a lower-dimensional picture, a "shadow" of this object when viewed from its (in some sense; see below) most informative viewpoint. This is done by using only the first few principal components so that the dimensionality of the transformed data is reduced.

3

You want to sort your cider collection along meaningful variables or connections of variables. What model will you use?

PCA

4

How many PCs can there be at maximum in your data?

Not more then original variables.

5

How many H0 hypotheses are there in a two-way ANOVA?

H0(A)
H0(B)
H0(AB)

6

The measurement error in repeated measures can be either ...

a random error or
a systematic error.

7

Examples for a nominal scale:

gender, nationality, group-names

8

Examples for ordinal scale:

rank order, Likert scale

9

Examples for interval scale:

no natural zero:
degree Celsius

10

Examples for ratio scale:

zero means there is nothing of it!
degree Kelvin
body height
counts

11

Describe logistic regression!

Like multiple regression, but the DV is a dichotomous variable. Logistic regression estimates the probability of the DV occurring as the value of the IV changes.
E.g: What are the odds of a suicide occurring at various levels of alcohol use?

12

Define the coefficient of variation!

In probability theory and statistics, the coefficient of variation (CV) is a normalized measure of dispersion of a probability distribution or frequency distribution.

13

Define standard error!

The standard error is the standard deviation of the sampling distribution of a statistic.