BBS1003 - Introduction Into Statistical Methods an der Maastricht University | Karteikarten & Zusammenfassungen

# Lernmaterialien für BBS1003 - Introduction into statistical methods an der Maastricht University

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TESTE DEIN WISSEN

What is the difference between a bar chart and a histogram?

Lösung anzeigen
TESTE DEIN WISSEN

- bar chart: bars are not connected ( qualitative variables)

- histogram: bars are continuous with the next one (quantitative variables)

Lösung ausblenden
TESTE DEIN WISSEN

What is the difference between a bar chart and a histogram?

Lösung anzeigen
TESTE DEIN WISSEN

- bar chart: bars are not connected ( qualitative variables)

- histogram: bars are continuous with the next one (quantitative variables)

Lösung ausblenden
TESTE DEIN WISSEN

Describe the measures of central tendency. For which variables are they appropriate?

Lösung anzeigen
TESTE DEIN WISSEN

- mean: sum of the values divided by the number of values (-> quantitative variables)

- median: middle values of ordered data (-> ordinal and quantitative variables)

- mode: most common value (-> quantitative and qualitative variables)

Lösung ausblenden
TESTE DEIN WISSEN

Explain the measures of variability

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TESTE DEIN WISSEN

- range: maximum - minimum (IQR: range of the middle 50%, between first and third quartile)

- variance: average of the difference between each value and the mean squared

- standard deviation: square root of the variance -> approximately the average deviation

Lösung ausblenden
TESTE DEIN WISSEN

What are the characteristics of a normal distribution?

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TESTE DEIN WISSEN

- mean, median and mode are equal

- unimodal (only one peak)

- the 1sigma (68%), 2sigma (95%) and 3sigma (99,7%) rule applies

Lösung ausblenden
TESTE DEIN WISSEN

What is a characteristic of a positively/negatively skewed distribution?

Lösung anzeigen
TESTE DEIN WISSEN

- positively skewed: mean > median > mode

- negatively skewed: mean < median < mode

Lösung ausblenden
TESTE DEIN WISSEN

What is the z-score?

Lösung anzeigen
TESTE DEIN WISSEN

- the z-score standardizes, to see how far an observation is from the mean in terms of standard deviation, it has always the mean 0 and standard deviation 1

Z = x-µ/SD

Lösung ausblenden
TESTE DEIN WISSEN

How does the mean and the variance act if a distribution is shifted (x added or multiplied by x)?

Lösung anzeigen
TESTE DEIN WISSEN

a) multiplied by x:

- mean is multiplied by x

- variance is multiplied by x^2

- variance remains the same

Lösung ausblenden
TESTE DEIN WISSEN

What is the Pearson correlation coefficient?

Lösung anzeigen
TESTE DEIN WISSEN

- tells about the strength and direction of a correlation

- -1<r<0 (negative correlation) or 0<r1 (positive correlation)

- r = 0 --> no correlation

- r = 1 or -1 --> perfect correlation

Lösung ausblenden
TESTE DEIN WISSEN

What is the R-square? How to interpret it?

Lösung anzeigen
TESTE DEIN WISSEN

- the R-square compares the distance of observed values and estimated values to the mean and tells how well the regression line predicts the actual values. 0≤Rsquare≤1

- Interpretation: R-square is the percentage of variability of Y explained by the regression model.

Lösung ausblenden
TESTE DEIN WISSEN

What happens to the shape of a distribution after a Z-transformation?

Lösung anzeigen
TESTE DEIN WISSEN

- the shape remains the same

- the mean will be 0 and the standard deviation will be 1

Lösung ausblenden
TESTE DEIN WISSEN

What are the different types of variables?

Lösung anzeigen
TESTE DEIN WISSEN

- qualitative variables: nominal & ordinal

- quantitative variables: interval & ratio

Lösung ausblenden
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## Beispielhafte Karteikarten für deinen BBS1003 - Introduction into statistical methods Kurs an der Maastricht University - von Kommilitonen auf StudySmarter erstellt!

Q:

What is the difference between a bar chart and a histogram?

A:

- bar chart: bars are not connected ( qualitative variables)

- histogram: bars are continuous with the next one (quantitative variables)

Q:

What is the difference between a bar chart and a histogram?

A:

- bar chart: bars are not connected ( qualitative variables)

- histogram: bars are continuous with the next one (quantitative variables)

Q:

Describe the measures of central tendency. For which variables are they appropriate?

A:

- mean: sum of the values divided by the number of values (-> quantitative variables)

- median: middle values of ordered data (-> ordinal and quantitative variables)

- mode: most common value (-> quantitative and qualitative variables)

Q:

Explain the measures of variability

A:

- range: maximum - minimum (IQR: range of the middle 50%, between first and third quartile)

- variance: average of the difference between each value and the mean squared

- standard deviation: square root of the variance -> approximately the average deviation

Q:

What are the characteristics of a normal distribution?

A:

- mean, median and mode are equal

- unimodal (only one peak)

- the 1sigma (68%), 2sigma (95%) and 3sigma (99,7%) rule applies

Q:

What is a characteristic of a positively/negatively skewed distribution?

A:

- positively skewed: mean > median > mode

- negatively skewed: mean < median < mode

Q:

What is the z-score?

A:

- the z-score standardizes, to see how far an observation is from the mean in terms of standard deviation, it has always the mean 0 and standard deviation 1

Z = x-µ/SD

Q:

How does the mean and the variance act if a distribution is shifted (x added or multiplied by x)?

A:

a) multiplied by x:

- mean is multiplied by x

- variance is multiplied by x^2

- variance remains the same

Q:

What is the Pearson correlation coefficient?

A:

- tells about the strength and direction of a correlation

- -1<r<0 (negative correlation) or 0<r1 (positive correlation)

- r = 0 --> no correlation

- r = 1 or -1 --> perfect correlation

Q:

What is the R-square? How to interpret it?

A:

- the R-square compares the distance of observed values and estimated values to the mean and tells how well the regression line predicts the actual values. 0≤Rsquare≤1

- Interpretation: R-square is the percentage of variability of Y explained by the regression model.

Q:

What happens to the shape of a distribution after a Z-transformation?

A:

- the shape remains the same

- the mean will be 0 and the standard deviation will be 1

Q:

What are the different types of variables?

A:

- qualitative variables: nominal & ordinal

- quantitative variables: interval & ratio

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