Question 835861
In a certain store, there is a 0.04 probability that the scanned price in the bar code scanner will not match the advertised price. The cashier scans 874 items.
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Note: Binomial problem with n = 874 and p(mismatch) = 0.04
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(a-1) What is the expected number of mismatches? (Round your answer to nearest whole number.)
mean = expected number = 874*0.04 = 34.96 
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(a-2) 
What is the standard deviation? (Use rounded expected number for the calculation of standard deviation. Round your final answer to 4 decimal places.) 
Standard deviation = sqrt(npq) = sqrt(34.96*0.96) = 5.79
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(b) 
What is the probability of at least 29 mismatches? (Round the value of z to 2 decimals. Use Appendix C-2 to find probabilities. Round your final answer to 4 decimal places.)
Comment: I can't tell what your C-2 Table looks like.
The problem can be worked as a Binomial or as a Normal
approximation to a Binomial.
If the latter:
P(29<= x <=874) = P(28.5<= x <=874.5)
z(28.5) = (28.5-34.96)/5.79 = -1.12
z(874.5)= (874.5-34.96)/5.79 = hugh
Probability = p(z > -1.12) = 0.8677
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(c) 
What is the probability of more than 43 mismatches? (Round the value of z to 2 decimals. Use Appendix C-2 to find probabilities. Round your final answer to 4 decimal places.) 
Probability = P(z > 1.2850) = 0.0994
Your answer was 0.0740

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Cheers,
Stan H.
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