Final answer:
To find the probability that a sample of 15 30-second commercials cost more than $55 million, we use the z-score formula and look up the probability in the standard normal distribution table. the probability that a sample of 15 commercials cost more than $55 million is approximately 0.0187, or 1.87%.
Step-by-step explanation:
To find the probability that a sample of 15 30-second commercials cost more than $55 million, we need to use the z-score formula. The z-score measures the number of standard deviations a data point is from the mean. First, we need to calculate the z-score for $55 million using the formula: z = (x - mean) / standard deviation.
Plug in the values: z = (55 - 6.5) / 0.5 = 97. Next, we can find the probability by looking up the z-score in the standard normal distribution table or using a calculator. The probability is the area under the curve to the right of the z-score. In this case, the probability that a sample of 15 commercials cost more than $55 million is approximately 0.0187, or 1.87%.