Question 1

Using R, which function is used to conduct association rule analysis?

Accepted Answer

The `apriori` function is used in R for mining association rules. It is part of the `arules` package and is specifically designed to find frequent itemsets and derive association rules from them.

Question 2

Eva is trying to figure out the total number of possible combinations for 130 inventory items. Calculate the number for Eva.

Accepted Answer

The answer of Eva is trying to figure out the...

Question 3

Eva is trying to figure out the total number of possible combinations for 50 inventory items. Calculate the number for Eva.

Accepted Answer

The answer of Eva is trying to figure out the...

Question 4

Martin wants to use Gower's coefficient to compute the distance for each variable and to convert it into a [0,1] scale. What analysis package will he use to run the analysis?

Accepted Answer

Gower's coefficient, a measure used for calculating similarity or dissimilarity between data points with mixed types of variables, can be computed using various statistical software packages, including R. R has specific packages (e.g., "cluster", "vegan") that can calculate Gower's distance directly, making it suitable for this task without the need for additional software like Analytic Solver or Excel.

Question 5

Of the following options, which is not accurate for clustering?

Accepted Answer

Cluster analysis involves organizing data into groups (or clusters) where members of the same group are more similar to each other than to those in other groups. It does not specifically relate to organizing small amounts of data against larger statistical sets; instead, it focuses on the overall structure and natural groupings within the data, regardless of the data size.

Question 6

The use of error sum of squares to measure the loss of information that occurs when observations are clustered describes which method?

Accepted Answer

Ward's method minimizes the within-cluster variance, which is equivalent to minimizing the error sum of squares. This method aims to choose the successive clustering steps in a way that the increase in the error sum of squares is minimized, effectively measuring the loss of information when observations are clustered.

Question 7

k-means clustering algorithm can be summarized as all of the following except for

Accepted Answer

K-means clustering algorithm works with numerical variables only because it relies on calculating distances between data points and cluster centers. Character variables cannot be directly used in these calculations without being converted to numerical values through some form of encoding.

Question 8

Tosh Marketing Group wants to identify customers who are likely to purchase high-end appliances for a new marketing campaign. After collecting data from recent customers, the following plot was created showing age and spend variables with 3 distinct clusters. Which cluster offers the best target with the highest spend for marketing materials?

Accepted Answer

The answer of Tosh Marketing Group wants to identify customers...

Question 9

In reviewing purchases at Costco on a given Saturday, 645 transactions out of 1,250 included toilet paper, detergent, and clothing or {toilet paper, detergent} => {clothing}. Calculate the support of the association rule.

Accepted Answer

The support of an association rule is calculated as the number of transactions including all items in the rule (both antecedent and consequent) divided by the total number of transactions. Here, 645 out of 1,250 transactions included all items, so the support is 645 / 1,250 = 0.516.

Question 10

In reviewing purchases at Costco on a given Saturday, 385 transactions out of 1,000 included toilet paper, detergent, and clothing or {toilet paper, detergent} => {clothing}. Calculate the support of the association rule.

Accepted Answer

The support of an association rule is calculated as the number of transactions containing both items (or itemsets) in the rule divided by the total number of transactions. Here, 385 out of 1,000 transactions included both itemsets, so the support is 385/1000 = 0.385.

Question 11

Toilet paper and detergent are the antecedent, where 950 of the 6,500 transactions include both items. Of the overall 6,500 transactions, 126 include toilet paper, detergent, and the consequent of clothing. Using the association rule, what is the confidence?

Accepted Answer

Confidence is calculated as the number of transactions including both the antecedent and consequent divided by the number of transactions including the antecedent. Here, it is 126/950 = 0.1326.

Question 12

Toilet paper and detergent are the antecedent, where 890 of the 10,000 transactions include both items. Of the overall 10,000 transactions, 234 include toilet paper, detergent, and the consequent of clothing. Using the association rule, what is the confidence?

Accepted Answer

The confidence of an association rule is calculated by dividing the number of transactions that include both the antecedent and the consequent by the number of transactions that include the antecedent. Here, the antecedent is toilet paper and detergent, and the consequent is clothing. There are 890 transactions with the antecedent and 234 transactions with both the antecedent and consequent. Thus, the confidence is 234 / 890 = 0.2629.

Question 13

Costco is known for lower prices for bulk items. After calculating the support and confidence values for {toilet paper} => {avocados}, there appears to be a strong association because a large percentage of customers purchase these items. However, to avoid assuming the strength of association, what option should be done to confirm the strength of the association?

Accepted Answer

Calculating the lift ratio helps in confirming the strength of the association between two items by measuring how much more often the items occur together than would be expected if they were statistically independent.

Question 14

Based on the following table, what is the frequency distribution of the most purchased item?

Accepted Answer

The answer of Based on the following table, what is...

Question 15

Based on the following table, what is the frequency distribution of the most purchased item?

Accepted Answer

The answer of Based on the following table, what is...

Question 16

Based on the following table, what is the proportion of the transactions that include both milk and bread?

Accepted Answer

The answer of Based on the following table, what is...

Question 17

Based on the following table, what is the proportion of the transactions that include both milk and bread?

Accepted Answer

The answer of Based on the following table, what is...

Question 18

The Corner Market is using 1,750 transactions on item purchases for analysis. Based on initial results, the manager noticed eggs and potato chips were frequently in the same transactions. After calculating the confidence and the expected confidence on the data, 0.44 and 0.61 respectively, they want to run a lift ratio to ensure there is a positive association. Calculate the lift ratio and determine if the association is positive or negative.

Accepted Answer

The lift ratio is calculated as confidence divided by expected confidence: 0.44 / 0.61 = 0.7213. Since the lift ratio is less than one, it indicates a negative association.

Question 19

The Corner Market is using 2,500 transactions on item purchases for analysis. Based on initial results, the manager noticed eggs and potato chips were frequently in the same transactions. After calculating the confidence and the expected confidence on the data, 0.54 and 0.62 respectively, they want to run a lift ratio to ensure there is a positive association. Calculate the lift ratio and determine if the association is positive or negative.

Accepted Answer

The lift ratio is calculated as the confidence divided by the expected confidence, which is 0.54 / 0.62 = 0.871. Since the lift ratio is under one, it indicates a negative association between the purchase of eggs and potato chips.

Question 20

Sara is a marketing analysis manager for a top cereal producer. Part of her job is to review product sales to grocery chains and if the contracted product shelf placement is the optimal location to maximize sales. Because of the large data sets, she is only interested in creating a small number of clusters to view the results. What type of clustering method would work best?

Accepted Answer

K-means clustering is the most suitable method for Sara's needs because it allows for the specification of the number of clusters beforehand, making it ideal for analyzing large datasets when only a small number of clusters is desired. This method is efficient for quickly categorizing data into a predefined number of clusters, which aligns with Sara's goal of reviewing product sales and shelf placement optimality without needing to sift through an overly detailed or complex cluster structure.

Quiz 11: Unsupervised Data Mining

Using R, which function is used to conduct association rule analysis?

Eva is trying to figure out the total number of possible combinations for 130 inventory items. Calculate the number for Eva.

Eva is trying to figure out the total number of possible combinations for 50 inventory items. Calculate the number for Eva.

Martin wants to use Gower's coefficient to compute the distance for each variable and to convert it into a [0,1] scale. What analysis package will he use to run the analysis?

Of the following options, which is not accurate for clustering?

The use of error sum of squares to measure the loss of information that occurs when observations are clustered describes which method?

k-means clustering algorithm can be summarized as all of the following except for

In reviewing purchases at Costco on a given Saturday, 645 transactions out of 1,250 included toilet paper, detergent, and clothing or {toilet paper, detergent} => {clothing}. Calculate the support of the association rule.

In reviewing purchases at Costco on a given Saturday, 385 transactions out of 1,000 included toilet paper, detergent, and clothing or {toilet paper, detergent} => {clothing}. Calculate the support of the association rule.

Toilet paper and detergent are the antecedent, where 950 of the 6,500 transactions include both items. Of the overall 6,500 transactions, 126 include toilet paper, detergent, and the consequent of clothing. Using the association rule, what is the confidence?

Toilet paper and detergent are the antecedent, where 890 of the 10,000 transactions include both items. Of the overall 10,000 transactions, 234 include toilet paper, detergent, and the consequent of clothing. Using the association rule, what is the confidence?

Based on the following table, what is the frequency distribution of the most purchased item?

Based on the following table, what is the frequency distribution of the most purchased item?

Based on the following table, what is the proportion of the transactions that include both milk and bread?

Based on the following table, what is the proportion of the transactions that include both milk and bread?