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The average number of days that construction workers miss per year is 11. The standard deviation is 2.3. The average number of days that factory workers miss per year is 8 with a standard deviation of 1.8. Which class is more variable in terms of days missed?

Short Answer

Expert verified
Factory workers are more variable with a CV of 22.5% compared to construction workers' 20.91%.

Step by step solution

01

Understand the Problem

We need to compare the variability of days missed by construction workers and factory workers. The variability can be understood by considering the standard deviation relative to the average using the coefficient of variation (CV).
02

Calculate Coefficient of Variation for Construction Workers

The Coefficient of Variation (CV) is calculated using the formula \( CV = \frac{\text{Standard Deviation}}{\text{Mean}} \times 100 \). For construction workers, \( CV = \frac{2.3}{11} \times 100 \approx 20.91\% \).
03

Calculate Coefficient of Variation for Factory Workers

Using the CV formula again for factory workers: \( CV = \frac{1.8}{8} \times 100 = 22.5\% \).
04

Compare the Coefficients of Variation

The higher the CV, the more variable the data is relative to its mean. Compare the CVs to determine which group has more variability: - Construction workers: \( 20.91\% \)- Factory workers: \( 22.5\% \) Factory workers have a higher CV, indicating more variability.

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Key Concepts

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

Variability of Data
Variability is an essential concept in statistics that measures how spread out data points are in a dataset. If the data points differ significantly from each other, the dataset has high variability. On the other hand, if the data points are close to the average value, the dataset exhibits low variability. In the context of comparing construction and factory workers, we assess variability to determine which group's attendance is more inconsistent. Variability helps us understand how reliable or predictable the data points are.

To evaluate variability, statisticians often use various measures such as range, variance, and the coefficient of variation (CV). The CV is a particularly useful measure because it expresses the standard deviation as a percentage of the mean, enabling easy comparisons across different datasets. For instance, in our example, the coefficient of variation helps us directly compare the variability of days missed between construction and factory workers regardless of their different means. A higher CV indicates greater variability in the dataset, meaning more inconsistency relative to the average.
Understanding Standard Deviation
Standard deviation is a widely used measure of variability. It shows how much individual data points deviate from the mean, or average, of the dataset. In simple terms, it's the average distance each data point is from the mean. A smaller standard deviation indicates data points are clustered around the mean and hence, less variability.

For our exercise, the standard deviation for construction workers is 2.3 days, and for factory workers, it is 1.8 days. This means that on average, the number of days missed by construction workers deviates by 2.3 days from the mean of 11 days. Similarly, factory workers' missed days vary by 1.8 days from their mean of 8 days. However, when comparing datasets with different averages, the coefficient of variation becomes a more effective tool as it considers the standard deviation relative to the mean.
The Role of Statistical Analysis
Statistical analysis involves systematic methods to collect, review, analyze, and draw conclusions from data. It is a critical tool in making informed decisions based on numeric data. In our exercise, statistical analysis is applied to compare the variability of days missed by two distinct groups of workers, hence allowing for an objective evaluation.

By employing the coefficient of variation, we gain insight into the relative variability of the two datasets. Statistical analysis facilitates a better understanding of how each group's absenteeism fluctuates relative to the average number of days missed. With the factory workers having a higher CV than construction workers, it indicates more inconsistency in their attendance. These insights might guide management decisions and help target interventions more effectively. Overall, statistical analysis transforms raw data into meaningful information that can direct strategies and resource allocation.

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