Replacement times for TV sets are normally distributed with a mean of 8.2 years and a standard deviation of 1.1 years. Find the probability a randomly selected TV will have a replacement time less than 5 years (round to three decimal places). 0.0018

MATLAB: An Introduction with Applications
6th Edition
ISBN:9781119256830
Author:Amos Gilat
Publisher:Amos Gilat
Chapter1: Starting With Matlab
Section: Chapter Questions
Problem 1P
icon
Related questions
Question
100%
Help please
**Understanding Probability: Replacement Times for TV Sets**

When considering replacement times for TV sets, data shows that this variable follows a normal distribution. Here we present a specific example to demonstrate this concept and guide you on how to calculate probabilities for normally distributed variables:

### Problem Statement
Replacement times for TV sets are normally distributed with:
- **Mean (μ)**: 8.2 years
- **Standard Deviation (σ)**: 1.1 years

**Question**: What is the probability that a randomly selected TV will have a replacement time less than 5 years? The answer should be rounded to three decimal places.

### Solution
To find this probability, we need to calculate the Z-score, which represents the number of standard deviations a value (X) is away from the mean. The Z-score formula is:

\[ Z = \frac{X - \mu}{σ} \]

For this problem:
- \( X = 5 \) years
- \( \mu = 8.2 \) years
- \( σ = 1.1 \) years

### Calculation
\[ Z = \frac{5 - 8.2}{1.1} = \frac{-3.2}{1.1} \approx -2.91 \]

Using the Z-score table or a normal distribution calculator, a Z-score of approximately -2.91 corresponds to a cumulative probability near **0.0018**.

Therefore, the probability that a randomly selected TV will have a replacement time less than 5 years is **0.0018**.

### Explanation
This result (0.0018) indicates that there is a **0.18% chance** that a TV will need to be replaced in less than 5 years. This low probability highlights that it is quite rare for TVs (under these distributions) to require replacement in such a short time frame.

By understanding this calculation, you can better appreciate the applications of normal distribution and probability in real-world scenarios, such as estimating product lifespans and making informed decisions based on statistical evidence.
Transcribed Image Text:**Understanding Probability: Replacement Times for TV Sets** When considering replacement times for TV sets, data shows that this variable follows a normal distribution. Here we present a specific example to demonstrate this concept and guide you on how to calculate probabilities for normally distributed variables: ### Problem Statement Replacement times for TV sets are normally distributed with: - **Mean (μ)**: 8.2 years - **Standard Deviation (σ)**: 1.1 years **Question**: What is the probability that a randomly selected TV will have a replacement time less than 5 years? The answer should be rounded to three decimal places. ### Solution To find this probability, we need to calculate the Z-score, which represents the number of standard deviations a value (X) is away from the mean. The Z-score formula is: \[ Z = \frac{X - \mu}{σ} \] For this problem: - \( X = 5 \) years - \( \mu = 8.2 \) years - \( σ = 1.1 \) years ### Calculation \[ Z = \frac{5 - 8.2}{1.1} = \frac{-3.2}{1.1} \approx -2.91 \] Using the Z-score table or a normal distribution calculator, a Z-score of approximately -2.91 corresponds to a cumulative probability near **0.0018**. Therefore, the probability that a randomly selected TV will have a replacement time less than 5 years is **0.0018**. ### Explanation This result (0.0018) indicates that there is a **0.18% chance** that a TV will need to be replaced in less than 5 years. This low probability highlights that it is quite rare for TVs (under these distributions) to require replacement in such a short time frame. By understanding this calculation, you can better appreciate the applications of normal distribution and probability in real-world scenarios, such as estimating product lifespans and making informed decisions based on statistical evidence.
Expert Solution
steps

Step by step

Solved in 2 steps with 2 images

Blurred answer
Knowledge Booster
Point Estimation, Limit Theorems, Approximations, and Bounds
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, statistics and related others by exploring similar questions and additional content below.
Recommended textbooks for you
MATLAB: An Introduction with Applications
MATLAB: An Introduction with Applications
Statistics
ISBN:
9781119256830
Author:
Amos Gilat
Publisher:
John Wiley & Sons Inc
Probability and Statistics for Engineering and th…
Probability and Statistics for Engineering and th…
Statistics
ISBN:
9781305251809
Author:
Jay L. Devore
Publisher:
Cengage Learning
Statistics for The Behavioral Sciences (MindTap C…
Statistics for The Behavioral Sciences (MindTap C…
Statistics
ISBN:
9781305504912
Author:
Frederick J Gravetter, Larry B. Wallnau
Publisher:
Cengage Learning
Elementary Statistics: Picturing the World (7th E…
Elementary Statistics: Picturing the World (7th E…
Statistics
ISBN:
9780134683416
Author:
Ron Larson, Betsy Farber
Publisher:
PEARSON
The Basic Practice of Statistics
The Basic Practice of Statistics
Statistics
ISBN:
9781319042578
Author:
David S. Moore, William I. Notz, Michael A. Fligner
Publisher:
W. H. Freeman
Introduction to the Practice of Statistics
Introduction to the Practice of Statistics
Statistics
ISBN:
9781319013387
Author:
David S. Moore, George P. McCabe, Bruce A. Craig
Publisher:
W. H. Freeman