Business Analytics Exam 2

The newest model of smart car is supposed to get excellent gas mileage. A thorough study showed that gas mileage (measured in miles per gallon) is normally distributed with a mean of 75 miles per gallon and a standard deviation of 10 miles per gallon. What value represents the 50th percentile of this distribution?

75

If a z-score is zero, then the corresponding x-value must be equal to the _____.

mean

Single linkage can be used to measure the distance between clusters that are the _____ in cluster analysis.

most similar

In k-means clustering, k represents the _____.

number of clusters

The _____ probability distribution can be used to estimate the number of vehicles that go through an intersection during the lunch hour.

poisson

The center of a normal curve is _____.

the mean of the distribution

All of the following are examples of discrete random variables except _____.

time

An experiment consists of determining the speed of automobiles on a highway by the use of radar equipment. The random variable in this experiment is a _____.

continuous random variable

A tree diagram used to illustrate the sequence of nested clusters produced by hierarchical clustering is known as a _____.

dendrogram

Probability is the _____.

numerical measure of the likelihood that an event will occur

Euclidean distance can be used to measure the distance between _____ in cluster analysis.

observations

The strength of a cluster can be measured by comparing the average distance in a cluster to the distance between cluster centroids. One rule of thumb is that the ratio for between-cluster distance to within-cluster distance should exceed what value for useful clusters?

one

Observation refers to the _____.

set of recorded values of variables associated with a single entity

A method for modifying variables that reduces bias prior to cluster analysis is _____.

standardization

The process of converting a word to its stem, or root word, is referred to as _____.

stemming

In the text mining process, the text is first preprocessed by deriving a smaller set of _____ from the larger set of words contained in a collection of documents.

tokens

The goal of _____ is to use the variable values to identify relationships between observations.

unsupervised learning

Which of the following statements is correct?

The binomial distribution is a discrete probability distribution and the normal distribution is a continuous probability distribution.

Which of the following is a discrete random variable?

The number of times a student guesses the answers to questions on a certain test