Data Science

Common Distributions

Question 1
Marks : +2 | -2
Pass Ratio : 100%
Which of the following is incorrect with respect to use of Poisson distribution?
Modeling event/time data
Modeling bounded count data
Modeling contingency tables
All of the mentioned
Explanation:
Poisson distribution is used for modeling unbounded count data.
Question 2
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Pass Ratio : 100%
__________ random variables are used to model rates.
Empirical
Binomial
Poisson
All of the mentioned
Explanation:
Poisson distribution is used to model counts.
Question 3
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Pass Ratio : 100%
The _________ basically states that the sample mean is consistent.
LAN
LLN
LWN
None of the mentioned
Explanation:
LLN stands for law of large numbers.
Question 4
Marks : +2 | -2
Pass Ratio : 100%
Point out the correct statement.
The exponent of a normally distributed random variables follows what is called the log-normal distribution
Sums of normally distributed random variables are again normally distributed even if the variables are dependent
The square of a standard normal random variable follows what is called chi-squared distribution
All of the mentioned
Explanation:
Many random variables, properly normalized, limit to a normal distribution.
Question 5
Marks : +2 | -2
Pass Ratio : 100%
Which of the following goal is incorrectly represented in the below figure?
Relationship between variables
Distribution of variables
Inference about relationships
Causal
Explanation:
Causal is not directly related to goal of statistical modelling.
Question 6
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The binomial random variables are obtained as the sum of iid Gaussian trials.
True
False
Explanation:
The binomial random variables are obtained as the sum of iid Bernoulli trials.
Question 7
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Pass Ratio : 100%
Which of the following theorem states that the distribution of averages of iid variables, properly normalized, becomes that of a standard normal as the sample size increases?
Central Limit Theorem
Central Mean Theorem
Centroid Limit Theorem
All of the mentioned
Explanation:
The Central Limit Theorem (CLT) is one of the most important theorems in statistics.
Question 8
Marks : +2 | -2
Pass Ratio : 100%
Point out the wrong statement.
The normal distribution is asymmetric and peaked about its mode
A constant times a normally distributed random variable is also normally distributed
Sample means of normally distributed random variables are again normally distributed
None of the mentioned
Explanation:
The normal distribution is symmetric and peaked about its mean.
Question 9
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Pass Ratio : 100%
Bernoulli random variables take (only) the values 1 and 0.
True
False
Explanation:
The Bernoulli distribution arises as the result of a binary outcome.
Question 10
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Pass Ratio : 100%
Which of the following form the basis for frequency interpretation of probabilities?
Asymptotics
Symptotics
Asymmetry
All of the mentioned
Explanation:
Asymptotics is the term for the behavior of statistics as the sample size.