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How Long Is the Line? To decide on the number of service counters needed for stores to be built in the future, a supermarket chain wanted to obtain information on the length of time (in minutes) required to service customers. To find the distribution of customer service times, a sample of 1000 customers' service times was recorded. Sixty of these are shown here: $$\begin{array}{rrrrrrrrrr}3.6 & 1.9 & 2.1 & 3 & 8 & 2 & 1.0 & 1.4 & 1.8 & 1.6 \\\1.1 & 1.8 & .3 & 1.1 & .5 & 1.2 & .6 & 1.1 & 8 & 1.7 \\\1.4 & .2 & 1.3 & 3.1& .4 & 2.3 & 1.8 & 4.5 & .9 & .7 \\\\.6 & 2.8 & 2.5 & 1.1 & .4 & 1.2 & .4 & 1.3 & 8 & 1.3 \\\1.1 & 1.2 & .8 & 1.0 & .9 & .7 & 3.1 & 1.7 & 1.1 & 2.2 \\\1.6 & 1.9 & 5.2 & .5 & 1.8 & .3 & 1.1 & .6 & .7 & .6\end{array}$$ a. Construct a stem and leaf plot for the data. b. What fraction of the service times are less than or equal to 1 minute? c. What is the smallest of the 60 measurements?

Short Answer

Expert verified
Answer: To calculate the fraction of service times less than or equal to 1 minute, count the number of service times in the data that is less than or equal to 1. Then, divide this count by the total number of observations, which is 60.

Step by step solution

01

Organize the data

Arrange the given data in ascending order, by sorting from the smallest to the largest values.
02

Construct a stem and leaf plot

A stem and leaf plot is a data display method that allows us to view the distribution of a set of data. It consists of "stems" and "leaves," where the stem represents the leading digit(s) and the leaf represents the trailing digit(s). In this case, since we are working with one decimal place, our stems will be the whole numbers and our leaves will be the decimal parts.
03

Calculate the fraction of service times less than or equal to 1 minute

To calculate the fraction of service times less than or equal to 1 minute, count the number of service times in the data that is less than or equal to 1. Then, divide this count by the total number of observations, which is 60.
04

Determine the smallest of the 60 measurements

Since the data has been organized in ascending order, the smallest measurement will be the first value in the sorted list.

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Data Visualization
Visualization plays a crucial role in interpreting and understanding the patterns within a dataset. In the context of the supermarket chain's analysis of customer service times, data visualization can tremendously improve comprehension of the underlying distribution. For instance, let's consider the importance of effectively presenting the service-time data, allowing quick identification of patterns, such as common service times or outliers. A stem and leaf plot serves as a robust visualization tool here. This plot segments the data into two parts - the 'stem,' representing the significant digit(s), and the 'leaf,' delineating the less significant digit(s). This bipartite arrangement creates a visual distribution, akin to a histogram, enabling one to easily discern the concentration of service times and immediately spot any anomalies.

Advantages of a Stem and Leaf Plot

  • Simple to construct, requiring no advanced software tools.
  • Facilitates a clear view of data distribution.
  • Compact representation that includes the actual data values.
  • Preserves the data's originality and can be used to reconstitute the original dataset.
Aided by such visualization techniques, decision-makers can derive insightful conclusions and implement strategies for resource allocation, such as determining the optimal number of service counters to mitigate long customer wait times.
Service Time Analysis
Service time analysis is essential for businesses aiming to optimize customer satisfaction and operational efficiency. By scrutinizing the length of time needed to service customers, companies can make informed decisions on staffing and the design of service delivery systems.In the exercise, the supermarket chain conducts a service time study as part of its logistical planning for future stores. They seek to understand the time distribution patterns via a sample of 1000 customers, with a snapshot provided for 60 of those customers. Analyzing service times not only indicates how long a customer waits but can also reveal service bottlenecks, peak hours, and staffing issues.

Interpreting Service Time Data

  • Identify the range of service times and peak service durations.
  • Determine the proportion of service times falling into categorically defined intervals—critical for ensuring short wait times.
  • Recognize the minimum and maximum service time values to understand best and worst-case service scenarios.
Such an examination permits a comprehensive evaluation of the current service model and the identification of improvement opportunities, thereby balancing workforce utilization and customer wait times.
Probability and Statistics
Probability and statistics are instrumental in analyzing real-world phenomena and making sense of data through patterns and inferences. In our supermarket scenario, statistical concepts help measure and predict customer service experiences based on service times.

Fraction of Service Times Less Than or Equal to One Minute

By calculating the fraction of service times that are less than or equal to one minute, we can assess the probability of a customer being served within this time frame. This statistical measure reflects service efficiency, with a higher proportion indicating a faster checkout process.

Understanding Minimal Service Time

Statistical analysis also focuses on finding the minimum or 'min' value in a dataset, which represents the quickest service rendered. This extreme value can be pivotal for setting baselines for expected service speed and for identifying when the service process operates at its peak efficiency. In essence, probability and statistics extend beyond abstract concepts to become vital tools for effective decision-making, enabling businesses to optimize operations and enhance customer experiences by interpreting data-driven insights.

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Most popular questions from this chapter

Computer Networks at Home As Americans become more knowledgeable about computer hardware and software, as prices drop and installation becomes easier, home networking of \(\mathrm{PCs}\) is expected to penetrate 27 percent of U.S. households by 2008 , with wireless technology leading the 12 way. $$\begin{array}{lcc}\multicolumn{2}{l} {\text { U.S. Home Networks (in millions) }} \\\\\text { Year } & \text { Wired } & \text { Wireless } \\\\\hline 2002 & 6.1 &1.7 \\\2003 & 6.5 & 4.5 \\\2004 & 6.2 & 8.7 \\\2005 & 5.7 & 13.7 \\\2006 & 4.9 & 19.1 \\\2007 & 4.1 & 24.0 \\\2008 & 3.4 & 28.2\end{array}$$ a. What graphical methods could you use to describe the data? b. Before you draw a graph, look at the predicted number of wired and wireless households in the table. What trends do you expect to see in the graphs? c. Use a line chart to describe the predicted number of wired households for the years 2002 to \(2008 .\) d. Use a bar chart to describe the predicted number of wireless households for the years 2002 to 2008 .

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Continuous or Discrete, again Identify each variable as continuous or discrete: a. Weight of two dozen shrimp b. A person's body temperature c. Number of people waiting for treatment at a hospital emergency room d. Number of properties for sale by a real estate agency e. Number of claims received by an insurance company during one day

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