Descriptive Statistics
Which measure of dispersion is based on the middle 50% of data?
Interquartile range
In Excel, which function calculates the mean of a set of numbers?
AVERAGE()
The process of using data from a sample to make conclusions about a population is called?
Statistical inference
Which chart highlights how often values fall within specific ranges rather than individual points?
Histogram
Which distribution models the number of failures before the first success?
Geometric
In a negatively skewed distribution, which of the following is most likely true?
a) Mean < Median < Mode
b) Mode < Median < Mean
c) Mean = Median = Mode
d) Mean > Median > Mode
Mean < Median < Mode
The function that calculates standard deviation
STDEV
The probability of rejecting the null hypothesis when it is false is known as
Power of the test
Which diagram preserves actual data points while also showing distribution shape?
Stem-and-leaf plot
Which discrete distribution is often used to model rare events?
Poisson
Which measure of central tendency is most appropriate when data are expressed in ratios or rates?
Harmonic mean or Geometric mean depending upon data
When programming in R, how can you load an external package not already installed?
install.packages("package_name")
Which type of error occurs when the sample overestimates the population parameter due to random chance?
Sampling error
Which diagram helps detect unusual observations or gaps in the dataset?
Boxplot
Which distribution is symmetric, bell-shaped, but has heavier tails than the normal?
Student’s t-distribution
Bowley’s coefficient of skewness is based on which summary values?
Quartiles and median
The default data structure for storing tabular data
Dataframe
Which problem occurs if the residuals in regression are correlated over time?
Autocorrelation
Which graph displays cumulative frequency against upper class boundaries to estimate medians and quartiles?
Ogive or cumulative frequency graph
Which distribution models the number of successes in sampling without replacement from a finite population?
Hypergeometric distribution
Which descriptive statistic is based on the ratio of the fourth central moment to the square of the variance?
Kurtosis
In R, the package most widely used to summarize data is:
dplyr
The assumption that residuals have equal variance?
Homoscedasticity
Which diagram represents hierarchical data with branches and nodes to show parent-child relationships?
Dendrogram/Tree Diagram
In reliability analysis, which distribution is most commonly used to model “time to failure” with varying hazard rates?
Weibull distribution