Statistics

posted by .

. A certain company makes 12-volt car batteries. After many years of product testing, the company knows that the average life of a battery is normally distributed, with a mean of 45 months and a standard deviation of 7 months. If the company does not want to make refunds for more than 10% of its batteries under the full-refund guarantee policy, for how long should the company guarantee the batteries (to the nearest month)? my answer was 36m is this correct
58 months
53 months
36 months
45 months
49 months

  • Statistics -

    Z = (score-mean)/SD

    Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the Z score = to that proportion. Put values in the above equation and solve for the score.

    It doesn't match your choice.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Statistics

    A certain company makes 12-volt car batteries. After many years of product testing, the company knows that the average life of a battery is normally distributed, with a mean of 45 months and a standard deviation of 7 months. If the …
  2. 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 …
  3. stats

    A manufacturer of automobile batteries claims that the distribution of battery life is 54 months with a standard deviation of 6 months. We take a random sample of 50 batteries. a. Find the probability that their mean life is less than …
  4. Statistics

    The lifetime of television produced by the Hishobi Company are normally distributed with a mean of 75 months and a standard deviation of 8 months. If the manufacture wants to have to replace only 1% of its televisions, what should …
  5. Statistics

    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 …
  6. statistics

    Urgen!! Statistics homework help? Your company is producing special battery packs for the most popular toy during the holiday season. The life span of the battery pack is known to be Normally distributed with a mean of 250 hours and
  7. 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 …
  8. Math

    LongLast Inc. produces car batteries. The mean life of these batteries is 60 months. The distribution of the battery life closely follows the normal probability distribution with a standard deviation of 8 months. As part of its testing …
  9. 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 …
  10. math

    the battery lifetime is normally distributed for large samples with a standard deviation of 70 days. if 16% of the batteries have a lifetime of 850 or higher, what is the average battery life?

More Similar Questions