SOLUTION: Mattel Corporation produces a remote-controlled car that requires three AA batteries. The mean life of these batteries in this product is 34 hours. The distribution of the battery

Question 862984: Mattel Corporation produces a remote-controlled car that requires three AA batteries. The mean life of these batteries in this product is 34 hours. The distribution of the battery lives closely follows the normal probability distribution with a standard deviation of 5.5 hours. As a part of their testing program Sony tests samples of 25 batteries.
What can you say about the shape of the distribution of sample mean?

What is the standard error of the distribution of the sample mean? (Round your answer to 4 decimal place.)

What proportion of the samples will have a mean useful life of more than 36 hours? (Round your answer to 4 decimal place.)

What proportion of the sample will have a mean useful life greater than 33.5 hours? (Round your answer to 4 decimal place.)
What proportion of the sample will have a mean useful life between 33.5 and 36 hours? (Round your answer to 4 decimal place.)

Answer by ewatrrr(24785) (Show Source): You can put this solution on YOUR website!



Hi

What is the standard error of the distribution of the sample mean?  = 1.1

 What proportion of the samples will have a mean useful life of more than 36 hours? 

normalcdf(36,100, 34,1.1) |100 a placeholder  0r P(z >2/1.1) = 3.45%

 What proportion of the sample will have a mean useful life greater than 33.5 hours? 

normalcdf(33.5,100, 34,1.1)  0r  P(z > -.5/1.1) = 67.53%

 What proportion of the sample will have a mean useful life between 33.5 and 36 hours? 

normalcdf(33.5,36, 34,1.1)  0r 67.53 - 3.45 = 64.08%

first are TI instructions(recommended) 'Or' is using z and z-calculator

Tables are fine.  Calculators quicker..so as one not loses there train of thought as to important concepts. 

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