Question

A report in the American Journal of Public Health (AJPH) examined the amount of lead in the printing on soft plastic bread wrappers. The article stated that the population mean amount of lead on a wrapper is 26 mg, with a population standard deviation of 6 mg. Researchers at RIT will obtain a random sample of 45 soft plastic bread wrappers from local grocery stores. Using the shape, center and spread already established in the previous problems...

What is the probability that the researchers’ sample mean will be less than 25 mg?
Question 4 options:
0.434
0.132
0.566
0.868

Answer 1

0.566

Explanation:

Firstly, we can use the Z-score formula to calculate the Z-score of 25 in our given data: Z = (25 - 26)/6 = -1/6 Next, we can use the Z-table to look up the probability of the given Z-score which is -1/6.

Probability = 0.566