#1
Which of the following measures of central tendency is most affected by outliers?
Mean
ExplanationThe mean is sensitive to extreme values, making it highly affected by outliers.
#2
Which type of graph is most appropriate for visualizing the relationship between two quantitative variables?
Scatter plot
ExplanationA scatter plot is the preferred graph for displaying the relationship between two quantitative variables.
#3
In a normal distribution, what percentage of data falls within one standard deviation of the mean?
68%
ExplanationApproximately 68% of the data in a normal distribution lies within one standard deviation of the mean.
#4
Which graphical representation is used to display the distribution of data and its quartiles?
Box plot
ExplanationA box plot visually displays the distribution of data, including quartiles and potential outliers.
#5
What is the primary purpose of a histogram?
To display the distribution of a single quantitative variable
ExplanationA histogram is used to visually represent the distribution of a single quantitative variable by dividing the data into bins.
#6
What does the standard deviation measure in a dataset?
Data dispersion
ExplanationStandard deviation quantifies the spread or dispersion of data points in a dataset.
#7
Which correlation coefficient value indicates the strongest relationship between two variables?
1
ExplanationA correlation coefficient of 1 signifies a perfect positive linear relationship between two variables.
#8
What does a p-value less than 0.05 typically indicate in hypothesis testing?
The null hypothesis can be rejected
ExplanationA p-value less than 0.05 suggests that there is enough evidence to reject the null hypothesis in hypothesis testing.
#9
What is the main difference between T-tests and Z-tests?
Z-tests are used for large sample sizes, while T-tests are used for small sample sizes
ExplanationZ-tests are suitable for large samples, while T-tests are employed for smaller sample sizes in hypothesis testing.
#10
Which measure is used to assess the skewness of data distribution?
Skewness
ExplanationSkewness is a measure of the asymmetry or lack of symmetry in a data distribution.
#11
In time series analysis, what does the term 'seasonality' refer to?
Trends that repeat at specific regular intervals within a year
ExplanationSeasonality in time series analysis refers to recurring patterns or trends at specific intervals, often within a year.
#12
What statistical test is used to compare the means of two related samples?
Paired T-test
ExplanationThe Paired T-test is employed to compare the means of two related samples, such as before and after measurements.
#13
In a regression analysis, what does an R-squared value of 1 indicate?
Perfect positive linear relationship
ExplanationAn R-squared value of 1 indicates that all variability in the dependent variable is explained by the independent variable, representing a perfect positive linear relationship.
#14
What is the purpose of using ANOVA (Analysis of Variance) in statistical analysis?
To compare means of more than two groups
ExplanationANOVA is employed to assess whether there are any statistically significant differences between the means of three or more independent groups.
#15
Which statistical test is appropriate for comparing the means of more than two independent groups?
One-way ANOVA
ExplanationOne-way ANOVA is used to compare means when there are three or more independent groups.
#16
Which test is used to determine if there are significant differences between the distributions of two independent samples?
Mann-Whitney U test
ExplanationThe Mann-Whitney U test assesses whether there are significant differences between the distributions of two independent samples, especially when assumptions of parametric tests are not met.
#17
What does the coefficient of determination (R^2) indicate in linear regression analysis?
The proportion of the variance in the dependent variable that is predictable from the independent variable(s)
ExplanationThe coefficient of determination (R^2) quantifies the proportion of the variance in the dependent variable that can be explained by the independent variable(s) in linear regression analysis.
#18
What is the purpose of performing a Box-Cox transformation in data preprocessing?
To normalize the residuals in regression analysis
ExplanationThe Box-Cox transformation is used to stabilize variance and normalize residuals in regression analysis.
#19
Which of the following is a non-parametric statistical test?
Kruskal-Wallis H test
ExplanationThe Kruskal-Wallis H test is a non-parametric test used to determine if there are differences between three or more independent groups.