ACME Manufacturing claims that its cell phone batteries last more than 32 hours on average in a certain type of cell phone. Tests on a random sample of 18 batteries showed a mean battery life of 37.8 hours with a population standard deviation of 10 hours. Is the mean battery life greater than the 32 hour claim? Answer the following questions using a significance level of alpha = 0.05.

We can conclude that the battery life is greater than the 32 hour claim.

Step-by-step explanation:

The null hypothesis is:

The alternate hypotesis is:

Our test statistic is:

In which X is the statistic, is the mean, is the standard deviation and n is the size of the sample.

In this problem, we have that:

So

We need to find the probability of finding a mean time greater than 37.8. If it is 5% of smaller(alpha = 0.05.), we can conclude that the battery life is greater than the 32 hour claim.

Probability of finding a mean time greater than 37.8

1 subtracted by the pvalue of z = t = 2.46.

z = 2.46 has a pvalue of 0.9931

1 - 0.9931 = 0.0069 < 0.05

So we can conclude that the battery life is greater than the 32 hour claim.

answer: 1,380

step-by-step explanation:

1: you turn %15 into a decimal by moving the decimal point two places to the left.

2: and then you multiply .15 by 1,200 , which will get you 180.00

3: from there you will add 180 to 1,200

4: which will get you 1,380

hope it *im kind of slow so idk if my answer is right*

cant open file sorry!

step-by-step explanation: