Practice problem Submit answer Reset item The waiting time to get food at a fast-food restaurant is 4.5 minutes on average with standard deviation of 1.6 munutes. Suppose that a sample of 44 customers is randomly selected. A. What are the mean and standard deviation of the sample mean waiting time of 44 customers? Mean = minutes Standard Deviation (standard error of the mean) minutes Round standard error to 5 decimal places. B. What is the probability that the average waiting time of 44 customers is less than 4.3 minutes? Answer: Round to 4 decimal places. C. What is the probability that the average waiting time of 44 customers is greater than 4.7 minutes? Answer: Round to 4 decimal places. D. What is the probability that the average waiting time of 44 customers is between 4.3 and 4.7 minutes? Answer: Round to 4 decimal places. E. Why were we able to use the normal model in this case? Choose an appropriate explanation below. O Because the distribution of the sample mean is always normal, regardless of the sample size. O Because the distribution of the waiting time of customers at a fast food restaurant is normal. O Because the sample size is small, and we know that for small enough samples, the distribution of the sample mean is approximately normal. O Because the sample size is large, and we know that for large enough samples, the distribution of the sample mean is approximately normal. Use the following built-in tool to answer the question. If at any point you wish to reset the tool to the initial state, click on the "reset" button below it. Geogebra Applet Submit answer\f\f