Small Business Just Leased A New Color Laser Computer

A Small Business Just Leased A New Computer And Color Laser Printer

A small business has leased a new computer and color laser printer for 3 years. The service contract for the computer offers unlimited repairs for a fee of $100 a year plus a $25 service charge for each repair needed. The company’s research indicates that during a given year, 86% of these computers need no repairs, 9% need to be repaired at least once, 4% twice, and 1% three times, and none require more than three repairs. What is the standard deviation in the number of repairs for this kind of computer per year? Round to two decimal places.

---

Sample Paper For Above instruction

Introduction

Understanding the variability in the number of repairs needed for leased computers is crucial for small business budgeting and service planning. This paper aims to compute the standard deviation of repairs per year for a computer leased under specific service contract conditions, with repair probabilities derived from empirical research. The analysis employs probability concepts, expectation calculations, and variance formulas to arrive at an accurate measure of dispersion in repair needs, facilitating better financial and operational decision-making.

Probability Distribution and Data Analysis

The given probabilities indicate a discrete probability distribution for the number of repairs, X, per year. Specifically, P(X=0) = 0.86, P(X=1) = 0.09, P(X=2) = 0.04, and P(X=3) = 0.01. These probabilities sum to 1, satisfying the fundamental requirement for a probability distribution. The repair experiences are independent between years, and the probabilities reflect the likelihood of a computer requiring a certain number of repairs within a year.

The associated repair costs for each repair are $25 per repair charge plus a fixed $100 annual fee for the service contract. Therefore, for the repair count X, the total repair cost T can be expressed as:

\[ T = 100 + 25X \]

with X taking values 0, 1, 2, and 3.

Though the costs are relevant for financial analysis, calculating the standard deviation focuses on the variability in the number of repairs, X, which follows a probability distribution identified from the data.

Calculations of Expected Value and Variance

The mean number of repairs per year, E(X), is calculated as:

\[

E(X) = \sum_{i=0}^3 i \times P(X = i)

\]

which is:

\[

E(X) = 0 \times 0.86 + 1 \times 0.09 + 2 \times 0.04 + 3 \times 0.01 = 0 + 0.09 + 0.08 + 0.03 = 0.20

\]

Next, the second moment E(X^2) is necessary for variance calculation:

\[

E(X^2) = \sum_{i=0}^3 i^2 \times P(X = i)

\]

\[

E(X^2) = 0^2 \times 0.86 + 1^2 \times 0.09 + 2^2 \times 0.04 + 3^2 \times 0.01 = 0 + 0.09 + 4 \times 0.04 + 9 \times 0.01

\]

\[

E(X^2) = 0 + 0.09 + 0.16 + 0.09 = 0.34

\]

Variance of X, denoted as Var(X), is calculated as:

\[

Var(X) = E(X^2) - [E(X)]^2 = 0.34 - (0.20)^2 = 0.34 - 0.04 = 0.30

\]

The standard deviation, σ, is the square root of the variance:

\[

\sigma = \sqrt{Var(X)} = \sqrt{0.30} \approx 0.5477

\]

Rounded to two decimal places, the standard deviation is 0.55.

Conclusion

The standard deviation in the number of repairs per year for this computer is approximately 0.55 repairs. This indicates low variability, primarily concentrated around the mean of 0.2 repairs annually. Small business owners can utilize this information to understand the repair risk associated with leased computers, aiding in cost estimation and service planning.

References

  • Ross, S. M. (2014). Introduction to Probability Models (11th ed.). Academic Press.
  • Hogg, R. V., & Tanis, E. (2015). Probability and Statistics (9th ed.). Pearson.
  • Ott, R. L., & Longnecker, M. (2010). An Introduction to Statistical Methods & Data Analysis (6th ed.). Brooks/Cole.
  • Mooney, C., & Duval, R. (1993). Bootstrapping: A Nonparametric Approach to Statistical Inference. Sage Publications.
  • Casella, G., & Berger, R. L. (2002). Statistical Inference (2nd ed.). Duxbury.
  • Lehmann, E. L., & Casella, G. (1998). Theory of Point Estimation. Springer.
  • Freedman, D., Pisani, R., & Purves, R. (2007). Statistics (4th ed.). W. W. Norton & Company.
  • Wasserman, L. (2004). All of Statistics: A Concise Course in Statistical Inference. Springer.
  • Devore, J. L. (2015). Probability and Statistics for Engineering and the Sciences (8th ed.). Cengage Learning.
  • Gupta, S. C., & Kapoor, V. K. (2018). Fundamentals of Mathematical Statistics (13th ed.). S. Chand Publishing.