Statistics
posted by Mike .
A battery manufacturer is positive that its AA batteries last for 1,000 hours. However, you’re working for Consumer Reports and you don’t agree with what they say about their product. So, you buy 400 batteries and you test them out. Your findings are that the batteries last 990 hours on average with a standard deviation of 125. If you used a significance level of 1%, what is your opinion about the company’s batteries?
Respond to this Question
Similar Questions

statistics
The numbers of hours of life of a torch battery is normally distributed with a mean of 150 hours and standard deviation of 12 hours. In a quality control test, two batteries are chosen at random from a batch. If both batteries have … 
Statistics
the manufacturer of a certain brand of auto batteries claims the mean life of these batteries is 45 months. A consumer protection agency that wants to check this claim took a random sample of 36 such batteries and found the mean life … 
statistics
The Acme Company has developed a new battery. The engineer in charge claims that the new battery will operate continuously for at leas 7 minutes longer than the old battery. To test the claim, the company selects a simple random sample … 
Easy algebra
Mike is testing new batteries to determine if the batteries last as long as advertised. The actual life of one of the batteries was only 4 weeks, 2 days, and 13 hours even though the advertisement claimed it would last 3,000 hours. … 
statistics
A company produces batteries whose lifetimes are normally distributed with a mean of 100 hours. It is known that 90% of the batteries last at least 40 hours. (i). Estimate the standard deviation lifetime. (3 marks) (ii). What percentage … 
Statistics
Battery manufacturers compete on the basis of the amount of time their products last in cameras and toys. A manufacturer of alkaline batteries has observed that it's batteries last for an average of 26 hours when used in a toy racing … 
statistics
A laptop computer manufacturer found that by improving their battery design, they could increase the time that the laptop computer could be used on a single charge. To verify this improvement, they compared a sample of 10 laptops installed … 
Probablity
The life time of a certain kind of batteries has a mean life of 400 hours and standard deviation as 45 hours. Assuming the distribution of life to be normal, find i) the percentage of batteries with a life time of atleast 470 hours. … 
statistics
A manufacturer claims that the mean lifetime of its lithium batteries is 1400 hours. A homeowner selects 25 of these batteries and finds the mean lifetime to be 1380 hours with a standard deviation of 80 hours. Test the manufacturers … 
Statistics (Math 210)
Hi there, I am doing my statistics homework and am having trouble with a few problems. I sincerely appreciate any help I receive! :) A manufacturer claims that the mean lifetime of its lithium batteries if 1200 hours. A homeowner selects …