Interval estimation provides a/an ________ for the parameter of interest.

  • Exact value
  • Mean
  • Median
  • Range
Interval estimation provides a range (or interval) of values for the parameter of interest. This is more informative than a point estimate, as it gives a measure of uncertainty.

How can you detect the presence of interaction effects in your data?

  • By adding interaction terms in the regression model and checking their significance
  • By checking the coefficients of the independent variables
  • By comparing the fit of the model with and without polynomial terms
  • By examining the correlation between variables
To detect the presence of interaction effects in your data, you can include interaction terms in your regression model and then check the significance of these terms. If the interaction term is statistically significant, this suggests that the effect of one variable on the dependent variable depends on the level of another variable.

The function used to describe the likelihood of a random variable that is continuous is called a ________.

  • Cumulative Distribution Function
  • Probability Density Function
  • Probability Mass Function
  • Random Function
For continuous random variables, the probability density function (PDF) is used to specify the probability of the random variable falling within a particular range of values, as opposed to taking on any one value.

What are the implications of violating the assumption of homoscedasticity in ANOVA?

  • It can lead to incorrect conclusions about the differences between group means
  • It has no implications
  • It leads to a decrease in the F-statistic
  • It leads to an increase in the F-statistic
Violating the assumption of homoscedasticity (equal variances across groups) in ANOVA can lead to incorrect conclusions about the differences between group means, i.e., the results of the ANOVA test could be misleading. This might cause Type I errors (rejecting a true null hypothesis) or Type II errors (failing to reject a false null hypothesis).

What does 'silhouette score' represent in cluster analysis?

  • The average size of the clusters
  • The distance between clusters
  • The level of similarity within clusters and dissimilarity between clusters
  • The number of clusters
The silhouette score is a measure of the similarity of an object to its own cluster (cohesion) compared to other clusters (separation). It represents how similar an object is to its own cluster compared to other clusters. The score ranges from -1 to 1, with high values indicating that the object is well matched to its own cluster and poorly matched to neighboring clusters.

How does the effect size influence the power of a test?

  • Effect size has no influence on power
  • It depends on the sample size
  • Larger effect sizes decrease power
  • Larger effect sizes increase power
The power of a test is influenced by the effect size - the magnitude of the difference or relationship you're testing for. Larger effect sizes increase the power of a test because they create a larger signal relative to the noise, making it easier to detect an effect if one exists.

The Wilcoxon Signed Rank Test requires the differences to be ________.

  • continuous
  • nan
  • nominal
  • ordinal or interval
The Wilcoxon Signed Rank Test requires the differences to be ordinal or interval, because it takes into account the magnitude of the differences.

What is a significant factor in a two-way ANOVA?

  • An independent variable that affects the dependent variable
  • The method of data collection
  • The precision of the instruments used
  • The size of the sample
In a two-way ANOVA, a significant factor is an independent variable that has a significant effect on the dependent variable. It is determined based on the calculated p-value for the effect of that factor.

Which type of data is numerical: qualitative or quantitative?

  • Both
  • None
  • Qualitative
  • Quantitative
Quantitative data is numerical. It represents measurements or counts that can be quantified mathematically. For example, age, height, weight, or the number of objects are all quantitative data because they consist of numeric measurements.

When would you use a t-test instead of a Z-test?

  • All of the above
  • When the data is not normally distributed
  • When the population standard deviation is unknown
  • When the sample size is very large
T-tests are typically used when the population standard deviation is unknown. The sample size or normality of data isn't the primary deciding factor.