Answer :
The probability corresponding to a z-score of -4.67 is extremely small and close to zero. Therefore, the probability that the mean time of two deliveries will exceed one hour (60 minutes) is very low.
To calculate the probability that the mean time of two deliveries will exceed one hour (60 minutes), we need to use the sampling distribution of the mean and the properties of the normal distribution.
The mean delivery time for the supplier is 51.7 minutes, and the standard deviation is 9.5 minutes. Since we are interested in the mean time of two deliveries, we can consider it as the sum of two independent random variables, each following the same normal distribution.
The mean of the sum of two delivery times is:
Mean = 51.7 + 51.7 = 103.4 minutes
The variance of the sum of two delivery times is:
Variance = (9.5^2) + (9.5^2) = 180.5
To calculate the probability that the mean time of two deliveries will exceed one hour (60 minutes), we need to find the probability that the sum of two delivery times is greater than 60 minutes.
Standardized value = (60 - 103.4) / sqrt(180.5)
To find the corresponding probability, we need to calculate the z-score for the standardized value of (60 - 103.4) / sqrt(180.5). The z-score represents the number of standard deviations the value is from the mean.
Using the given values, we can calculate the z-score as follows:
Z = (60 - 103.4) / sqrt(180.5)
Calculating this expression:
Z = -43.4 / sqrt(180.5)
Using a calculator, we find that the value of the z-score is approximately -4.67.
Now, we can look up the probability corresponding to the z-score of -4.67 in the standard normal distribution table or use a statistical calculator.
The probability corresponding to a z-score of -4.67 is extremely small and close to zero. Therefore, the probability that the mean time of two deliveries will exceed one hour (60 minutes) is very low.
In conclusion, the probability is very close to zero.
learn more about mean here:
https://brainly.com/question/32635709
#SPJ11