Understanding the Distribution

Oct 13, 2025 by miodeya.com 131 views

Introduction

In today's digital age, the use of cell phones has become an integral part of our daily lives. Teenagers, in particular, spend a significant amount of time on their cell phones, which can have both positive and negative effects on their physical and mental health. In this article, we will explore the amount of daily time that teenagers spend on a brand A cell phone and calculate the percentage of teenagers who spend more than 3.1 hours on their cell phones.

Understanding the Distribution

The amount of daily time that teenagers spend on a brand A cell phone is normally distributed with a mean (μ) of 2.5 hours and a standard deviation (σ) of 0.6 hours. This means that the data follows a bell-shaped curve, with the majority of the data points clustered around the mean.

Calculating the Percentage

To calculate the percentage of teenagers who spend more than 3.1 hours on their cell phones, we need to use the z-score formula:

z = (X - μ) / σ

where X is the value we are interested in (3.1 hours), μ is the mean (2.5 hours), and σ is the standard deviation (0.6 hours).

Plugging in the values, we get:

z = (3.1 - 2.5) / 0.6 z = 0.6 / 0.6 z = 1

Using a Standard Normal Distribution Table

To find the percentage of teenagers who spend more than 3.1 hours on their cell phones, we need to use a standard normal distribution table (also known as a z-table). The z-table shows the area under the standard normal curve to the left of a given z-score.

Looking up the z-score of 1 in the z-table, we find that the area to the left of z = 1 is approximately 0.8413. This means that about 84.13% of the data points fall to the left of z = 1.

Finding the Percentage of Teenagers who Spend More than 3.1 Hours

Since we are interested in the percentage of teenagers who spend more than 3.1 hours on their cell phones, we need to find the area to the right of z = 1. This can be done by subtracting the area to the left of z = 1 from 1:

1 - 0.8413 = 0.1587

This means that approximately 15.87% of the data points fall to the right of z = 1. However, we are interested in the percentage of teenagers who spend more than 3.1 hours on their cell phones, which is the area to the right of z = 1. To find this percentage, we need to subtract the area to the left of z = 1 from 1:

1 - 0.8413 = 0.1587

However, this is the area to the right of z = 1, but we are interested in the area to the right of z = 1.5 (3.1 - 2.5 = 0.6 and 0.6 / 0.6 = 1 and 1 + 0.5 = 1.5). We need to find the area to the right of z = 1.5.

Looking up the z-score of 1.5 in the z-table, we find that the area to the left of z = 1.5 is approximately 0.9332. This means that about 93.32% of the data points fall to the left of z = 1.5.

Finding the Percentage of Teenagers who Spend More than 3.1 Hours

Since we are interested in the percentage of teenagers who spend more than 3.1 hours on their cell phones, we need to find the area to the right of z = 1.5. This can be done by subtracting the area to the left of z = 1.5 from 1:

1 - 0.9332 = 0.0668

This means that approximately 6.68% of the data points fall to the right of z = 1.5. However, we are interested in the percentage of teenagers who spend more than 3.1 hours on their cell phones, which is the area to the right of z = 1.5.

Conclusion

In conclusion, the percentage of teenagers who spend more than 3.1 hours on their cell phones is approximately 6.68%. This means that about 6.68% of the teenagers spend more than 3.1 hours on their cell phones, which is a significant amount of time.

References

[1] Moore, D. S., & McCabe, G. P. (2013). Introduction to the practice of statistics. W.H. Freeman and Company.
[2] Johnson, R. A., & Bhattacharyya, G. K. (2013). Statistics: Principles and methods. John Wiley & Sons.

Discussion

The amount of time that teenagers spend on their cell phones is a growing concern. Excessive cell phone use has been linked to various negative effects, including decreased attention span, increased risk of addiction, and decreased physical activity. Parents and educators should be aware of the potential risks associated with excessive cell phone use and take steps to promote healthy cell phone habits among teenagers.

Recommendations

Based on the results of this study, we recommend that parents and educators take the following steps to promote healthy cell phone habits among teenagers:

Set limits on cell phone use: Establish rules and guidelines for cell phone use, such as setting limits on screen time and encouraging physical activity.
Monitor cell phone use: Keep track of the amount of time teenagers spend on their cell phones and address any concerns or issues that arise.
Encourage physical activity: Promote physical activity and outdoor play to help teenagers develop healthy habits and reduce the risk of excessive cell phone use.
Educate teenagers: Teach teenagers about the potential risks associated with excessive cell phone use and encourage them to develop healthy cell phone habits.

Q: What is the normal distribution of the amount of daily time that teenagers spend on a brand A cell phone?

A: The normal distribution of the amount of daily time that teenagers spend on a brand A cell phone has a mean (μ) of 2.5 hours and a standard deviation (σ) of 0.6 hours.

Q: How do I calculate the percentage of teenagers who spend more than 3.1 hours on their cell phones?

A: To calculate the percentage of teenagers who spend more than 3.1 hours on their cell phones, you need to use the z-score formula:

z = (X - μ) / σ

where X is the value you are interested in (3.1 hours), μ is the mean (2.5 hours), and σ is the standard deviation (0.6 hours).

Q: What is the z-score for 3.1 hours?

A: The z-score for 3.1 hours is 1, since (3.1 - 2.5) / 0.6 = 0.6 / 0.6 = 1.

Q: How do I find the percentage of teenagers who spend more than 3.1 hours on their cell phones?

A: To find the percentage of teenagers who spend more than 3.1 hours on their cell phones, you need to use a standard normal distribution table (also known as a z-table). The z-table shows the area under the standard normal curve to the left of a given z-score.

Q: What is the area to the left of z = 1?

A: The area to the left of z = 1 is approximately 0.8413.

Q: What is the area to the right of z = 1?

A: The area to the right of z = 1 is approximately 1 - 0.8413 = 0.1587.

Q: What is the area to the left of z = 1.5?

A: The area to the left of z = 1.5 is approximately 0.9332.

Q: What is the area to the right of z = 1.5?

A: The area to the right of z = 1.5 is approximately 1 - 0.9332 = 0.0668.

Q: What is the percentage of teenagers who spend more than 3.1 hours on their cell phones?

A: The percentage of teenagers who spend more than 3.1 hours on their cell phones is approximately 6.68%.

Q: What are some recommendations for promoting healthy cell phone habits among teenagers?

A: Some recommendations for promoting healthy cell phone habits among teenagers include:

Set limits on cell phone use: Establish rules and guidelines for cell phone use, such as setting limits on screen time and encouraging physical activity.
Monitor cell phone use: Keep track of the amount of time teenagers spend on their cell phones and address any concerns or issues that arise.
Encourage physical activity: Promote physical activity and outdoor play to help teenagers develop healthy habits and reduce the risk of excessive cell phone use.
Educate teenagers: Teach teenagers about the potential risks associated with excessive cell phone use and encourage them to develop healthy cell phone habits.

Q: What are some potential risks associated with excessive cell phone use?

A: Some potential risks associated with excessive cell phone use include:

Decreased attention span: Excessive cell phone use can lead to decreased attention span and difficulty focusing on tasks.
Increased risk of addiction: Excessive cell phone use can lead to addiction, which can have negative effects on mental and physical health.
Decreased physical activity: Excessive cell phone use can lead to decreased physical activity, which can have negative effects on physical health.
Decreased social skills: Excessive cell phone use can lead to decreased social skills, which can have negative effects on mental health.

Q: How can parents and educators promote healthy cell phone habits among teenagers?

A: Parents and educators can promote healthy cell phone habits among teenagers by:

Setting limits on cell phone use
Monitoring cell phone use
Encouraging physical activity
Educating teenagers about the potential risks associated with excessive cell phone use

By following these recommendations, parents and educators can help promote healthy cell phone habits among teenagers and reduce the risk of excessive cell phone use.