SOLUTION: Suppose that 50 identical batteries are being tested. After 8 hours of continuous use, assume that a given battery is still operating with a probability of 0.70 and has failed with

Question 1124794: Suppose that 50 identical batteries are being tested. After 8 hours of continuous use, assume that a given battery is still operating with a probability of 0.70 and has failed with a probability of 0.30.
What is the probability that fewer than 25 batteries will last at least 8 hours?
Answer by Boreal(15235) (Show Source): You can put this solution on YOUR website!
The mean would be 35 batteries (50*0.7)
The variance would be 10.5 (mean*0.3)
The sd would be sqrt (10.5) or 3.24
the continuity correction factor would be z<(24.5-35)/3.24 of z< 10.5/3.24 =3.24
probability is 0.0006
Check 50C24*0.7^24*0.3^26=0.000592
50C23*0.7^24*0.3^27=0.00016
the others will be far smaller.
RELATED QUESTIONS
Suppose that 50 identical batteries are being tested. After 8 hours of continuous use,... (answered by lynnlo)

1.0 Points Suppose that 50 identical batteries are being tested. After 8 hours of... (answered by lynnlo)

Suppose that 50 identical batteries are being tested. After 8 hours of continuous use,... (answered by stanbon)

In a box of thrity aaa batteries there are three defective batteries. Two batteries are... (answered by katealdridge,stanbon)

The life of an alkaline battery in constant use is a normally distributed random variable (answered by Fombitz)

From experience, a battery manufacturer knows the probability of a battery being... (answered by Fombitz)

From experience, a battery manufacturer knows the probability of a battery being... (answered by solver91311)

3. From experience, a battery manufacturer knows the probability of a battery being... (answered by solver91311)

A large flashlight is powered by 5 batteries. Suppose that the life of a battery is... (answered by Boreal,Theo)