An Internet book retailer promises to ship all customer orders within 24 to 36 hours of receiving an order on its website. Actual shipment data for all computers shipped during the past month showed that the average delivery time was 30 hours, and the standard deviation was 4 hours. Is the company delivering Six Sigma quality to its customers? If not, then how much should the standard deviation of the process be reduced to get Six Sigma quality
Inverse Normal Distribution
The method used for finding the corresponding z-critical value in a normal distribution using the known probability is said to be an inverse normal distribution. The inverse normal distribution is a continuous probability distribution with a family of two parameters.
Mean, Median, Mode
It is a descriptive summary of a data set. It can be defined by using some of the measures. The central tendencies do not provide information regarding individual data from the dataset. However, they give a summary of the data set. The central tendency or measure of central tendency is a central or typical value for a probability distribution.
Z-Scores
A z-score is a unit of measurement used in statistics to describe the position of a raw score in terms of its distance from the mean, measured with reference to standard deviation from the mean. Z-scores are useful in statistics because they allow comparison between two scores that belong to different normal distributions.
Directions: Answer the following question in a Microsoft Excel document.
- An Internet book retailer promises to ship all customer orders within 24 to 36 hours of receiving an order on its website. Actual shipment data for all computers shipped during the past month showed that the average delivery time was 30 hours, and the standard deviation was 4 hours.
- Is the company delivering Six Sigma quality to its customers?
- If not, then how much should the standard deviation of the process be reduced to get Six Sigma quality?
- The production process for an electronic product has 12 major steps. If each of the first six production steps is at a 5-Sigma quality level and the remaining steps are at a 5.5 sigma quality level, calculate the total percentage of error-free products manufactured.
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