math foundations 20
posted by Ayane .
How do I solve normal distribution word problems? Ex
A manufacturer offers a warranty on it's coffee makers. The coffee makers have mean lifespan of 4.5 years, with standard deviation of 0.7 yeaes. For how long should the coffee makers be covered by the warranty, if the manufacturer wants to repair no more than 2.5% of the coffee makers sold?

you want x such that P(Z<x) = 0.025
That means that x must be more than 1.96 std below the mean. In this case, that's 3.128 years.
Respond to this Question
Similar Questions

MATH
Which of the following normal distributions has the smallest spread? 
finance
Laird Company sells coffee makers used in business offices. Its beginning inventory of coffee makers was 200 units at $45.00 per unit. During the year, Laird made two batch purchases of coffee makers. The first was a 300unit purchase … 
Math
I know that I have to use log to solve, but I am having a hard time with the word problems. Please help Coffee is best enjoyed at a temperature of 121° F. A restaurant owner wants to discover the temperature T at which he should serve … 
Statistics: Percentile Rank
A survey of college students was conducted during final exam week to assess the number of cups of coffee consumed each day. The mean number of cups was 5 with a standard deviation of 1.5 cups. The distribution was normal. A. What proportion … 
biostatistics
among coffee drinkers, men drink a mean of 3.2 cups per day with a standard deviation of 0.8 cups. Assume the number of coffee drinks per day follows a normal distribution. a. What proportion drinks 2 cups per day or more? 
statistics
Faculty in the psychology department at APUS consume an average of 5 cups of coffee per day with a standard deviation of 1.5. The distribution is normal. How many cups of coffee would an individual at the 25th percentile drink per … 
Financial accounting
Laird Company sells coffee makers used in business offices. Its beginning inventory of coffee makers was 200 units at $41 per unit. During the year, Laird made two batch purchases of coffee makers. The first was a 295unit purchase … 
Algebra
A manufacturer produces a 4cup and 8cup coffee maker. The 4cup maker takes 6 hours to produce and the 8cup takes 9 hours. The manufacturer has at most 500 hours of labor per week. a. Write an inequality to represent the number … 
math
A manufacturer produces a 4cup and 8cup coffee maker. The 4cup maker takes 6 hours to produce and the 8cup takes 9 hours. The manufacturer has at most 500 hours of labor per week. a. Write an inequality to represent the number … 
Math
You have to choose a battery brand to use in your smoke alarm. Company A's batteries have a mean lifespan of 1.2 years, with a standard deviation of 0.1 years. Company B's batteries have a mean lifespan of 1.5 years, with a standard …