SOLUTION: Life of Light Bulbs A certain type of light bulb has an average
life of 500 hours, with a standard deviation of 100 hours. The
length of life of the bulb can be closely approxima
Algebra.Com
Question 370437: Life of Light Bulbs A certain type of light bulb has an average
life of 500 hours, with a standard deviation of 100 hours. The
length of life of the bulb can be closely approximated by a normal
curve. An amusement park buys and installs 10,000 such
bulbs. Find the total number that can be expected to last for
each period of time.
Q:Find the shortest and longest lengths of life for the middle
80% of the bulbs.
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
Life of Light Bulbs A certain type of light bulb has an average
life of 500 hours, with a standard deviation of 100 hours. The
length of life of the bulb can be closely approximated by a normal
curve. An amusement park buys and installs 10,000 such
bulbs. Find the total number that can be expected to last for
each period of time.
Q:Find the shortest and longest lengths of life for the middle
80% of the bulbs.
----
The middle 80% has a left tail of 10% and a right tail of 10%
----
The z-value with a left tail of 10% = -1.2816
The z-value with a right tail of 10% = 1.2816
-----
Life cutoff for the lowest 10% = -1.2816*100+500 = 372 hrs.
---
Life cutoff for the top 10% = 1.2816*100+500 = 628 hrs
===================
Cheers,
Stan H.
RELATED QUESTIONS
Light Bulb Life Span • The life span of a certain type of light bulb is normally... (answered by stanbon)
I need help with my math today.I need to understand why i got these problems wrong on my... (answered by stanbon)
A light bulb company claims that the 40 watt light bulb it sells has an average life of... (answered by Theo)
A light bulb has an average life of 500 hours with a std. deviation of 100 hours. This... (answered by ewatrrr)
Light bulbs are measured in lumens (light output), watts (energy used), and hours (life). (answered by stanbon)
A quality engineer in a light bulb factory is planning a study to estimate the average... (answered by stanbon)
If light bulbs have lives that are normally distributed with a mean of 2500 hours and a... (answered by MathLover1)
A light bulb manufacturer guarantees that the mean life of a certain type of light bulb... (answered by Theo)
A company installs 5000 light bulbs, each with an average life of 500 hours, standard... (answered by stanbon)