How does the rate parameter affect the shape of a Poisson distribution?

  • All of the above
  • It determines the kurtosis of the distribution
  • It determines the skewness of the distribution
  • It does not affect the shape of the distribution
The rate parameter (lambda) in a Poisson distribution determines the average rate of occurrence per interval, which directly affects the shape of the distribution. Higher lambda values result in distributions that are less skewed to the right.

What does a null hypothesis represent in statistical testing?

  • A condition of no effect or no difference
  • A specific outcome of the experiment
  • An effect or difference exists
  • The sample size is large enough for the test
The null hypothesis is a statement in statistical inference which asserts that there is no significant difference between the set of observed and expected data.

How does Spearman's Rank Correlation react to outliers as compared to Pearson's correlation?

  • Both are equally sensitive to outliers
  • Less sensitive to outliers
  • More sensitive to outliers
  • Neither is sensitive to outliers
Spearman's Rank Correlation is less sensitive to outliers than Pearson's correlation. This is because Spearman's correlation is based on rank orders rather than raw data values, making it more robust against outliers.

When can we apply the Chi-square test for goodness of fit?

  • When the data are continuously distributed
  • When the data are normally distributed
  • When we have categorical data and want to see if it follows a specific distribution
  • When we want to compare means
The Chi-square test for goodness of fit is used when we have categorical data and we want to see if the data follows a specific distribution.

What is the concept of "Type I" error in the context of hypothesis testing?

  • Failing to reject a false null hypothesis
  • Failing to reject a true alternative hypothesis
  • Rejecting a false alternative hypothesis
  • Rejecting a true null hypothesis
A Type I error in hypothesis testing is the incorrect rejection of a true null hypothesis, often signified by the Greek letter alpha (α). In other words, a Type I error happens when the researcher incorrectly concludes that the null hypothesis is false when, in fact, it is true.

What is the effect of outliers on PCA?

  • It depends on the distribution of the data
  • They can distort the principal components
  • They enhance the performance of PCA
  • They have no effect on PCA
Outliers can significantly distort the principal components identified by PCA, as they can artificially inflate the variance along their direction. It's generally a good practice to address outliers before applying PCA.

Can PCA be used for both supervised and unsupervised learning?

  • No
  • Only for supervised learning
  • Only for unsupervised learning
  • Yes
No, PCA is a technique for unsupervised learning. It does not use any class label information in its algorithm, making it unsupervised. However, the transformed dataset from PCA can be used for subsequent supervised learning tasks.

What does a residual plot tell us about the fit of the model?

  • It indicates how well the model's predictions match the actual data
  • It indicates the variance of the residuals
  • It shows the correlation between the dependent and independent variables
  • It shows the relationship between the dependent and independent variables
A residual plot shows the residuals on the y-axis and the independent variable on the x-axis. If the points in a residual plot are randomly dispersed around the horizontal axis, a linear regression model is appropriate for the data; otherwise, a non-linear model is more appropriate.

ANOVA stands for Analysis of ________.

  • Value
  • Variables
  • Variance
  • Vectors
ANOVA stands for Analysis of Variance. It is a statistical method used to compare the means of two or more groups.

Bayes' theorem is a method for updating ________ probabilities based on new data.

  • conditional
  • joint
  • marginal
  • prior
Bayes' theorem is a principle in probability theory and statistics that describes how to update the probabilities of hypotheses (prior probabilities) when given evidence (new data).

What is the impact of outliers on the skewness of a distribution?

  • Outliers can decrease skewness
  • Outliers can either increase or decrease skewness
  • Outliers can increase skewness
  • Outliers do not impact skewness
Outliers can have a significant impact on the skewness of a distribution. An outlier can increase skewness if it is further from the mean in the direction of the skew. Conversely, an outlier can decrease skewness if it is further from the mean in the direction opposite to the skew. The extent of the impact depends on the value and direction of the outlier relative to the rest of the data.

________ is a popular method for cluster analysis that partitions the data into non-hierarchical clusters.

  • DBSCAN
  • Hierarchical
  • K-means
  • PCA
K-means is a popular method for cluster analysis that partitions the data into non-hierarchical clusters. The algorithm iteratively assigns each data point to one of the K clusters based on the feature similarity (distance).