1 points 1 6.3029 0 My Notes Ask Your Tea Quick Start Company makes 12-volt car
ID: 3331357 • Letter: 1
Question
1 points 1 6.3029 0 My Notes Ask Your Tea Quick Start Company makes 12-volt car batteries. After many years of product testing, the company knows that the average life of a Quick Start battery is normally distributed, with a mean of 45.2 months and a standard deviation of 9.5 months (a) If Quick Start guarantees a full refund on any battery that fails within the 36-month period after purchase, what percentage of its batteries will the company expect to replace? (Round your answer to two decimal places.) (b " Quick Start does not want to make refunds for more than 12% of its batteries under the full-refund guarantee policy for how long should the company guarantee the batteries (to the nearest month )? months Need Help?Explanation / Answer
mean = 45.2
std. dev. = 9.5
(a)
P(X < 36) = P(z < (36 - 45.2)/9.5) = P(z < -0.9684) = 0.1664
Hence 16.64% of its battereis the company expects to replace.
(b)
for 12%, z-value = -1.175
xbar = mean + z*sigma
xbar = 45.2 + (-1.175)*9.5 = 34.0375
Hence company should give the guarantee for 34 months
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.