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A battery manufacturer makes batteries that have a failure rate of .015. That is, 15 out of each 1,000 batteries are defective. What is the probability that a batch of 10,000 batteries will contain at least 175 defective batteries?
A. .01
B. .02
C. .03
D. .04
E. .015

Question

Help with AP Stats will fan and medal!!

A battery manufacturer makes batteries that have a failure rate of .015. That is, 15 out of each 1,000 batteries are defective. What is the probability that a batch of 10,000 batteries will contain at least 175 defective batteries?
A.	.01
B.	.02
C.	.03
D.	.04
E.	.015

tkhunny · Answer

You have a mean of 150 = np = 10000*0.015.
What is the standard deviation to be used in your Normal Approximation?

Or, were you planning to use the Binomial directly?