18 Questions
What do the sums of frequencies or relative frequencies in rows define?
The marginal distribution of the variable X
What is the meaning of fi. in the context of contingency tables?
The relative frequency of the group of individuals presenting modality xi of X
What is the formula for the relative frequency fij?
fij = nij / n
What is the meaning of n.j in the context of contingency tables?
The subtotal of the frequencies of the groups of individuals in the j-th column
What is the sum of the relative frequencies fij over all i and j?
1
What is the name of the distribution defined by the sums of frequencies or relative frequencies in columns?
The second marginal distribution
What is the purpose of correlation coefficients, scatterplots, and regression equations?
To summarize and interpret the strength and direction of the relationship between the quantitative variables.
What is X in the context of contingency tables?
The response of an individual to the variable X.
What is represented by nij in a contingency table?
The frequency of the group of individuals presenting both modality xi of X and modality yj of Y.
What is the purpose of a contingency table?
To summarize the frequency of different groups of individuals presenting different modalities of two variables.
What is the graphical representation of the relationship between two quantitative variables?
Scatter plot
What are the elements of a contingency table?
Rows representing the modalities of X and columns representing the modalities of Y.
What does the conditional distribution given the number of rooms is 4 represent?
The probability of the surface area given the number of rooms
What is the formula to calculate the conditional variance?
V (X|Y = yi ) = k X fX=xi |Y =yj x2i − m2X|Y =yi
What is independence in the context of statistical variables?
The absence of a relationship between two statistical variables
What is the condition for two variables to be independent?
fij = fi..f.j , ∀i = 1,.., k and j = 1,.., l
What is represented in a contingency table?
The joint probability distribution of two variables
What is an example of a statistical problem that can be represented by a contingency table?
The relationship between the number of rooms and surface area of dwellings
Quiz on contingency tables, relative frequencies, and modalities in statistics. Test your understanding of statistical concepts and formulas.
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