Delphine runs a put supply company and wants to reduce the return rate of her products. She adds more detail to the description of her products.

Before this change, her return rate was 6.6 out of every 100 sales. After the change, she sold 270 items and only 5 items were returned. What should she conclude at the 99.9% confidence level?

In answering this question, be sure to:

• Show your work on the calculated score (you may copy/paste commands from Excel to do this);
• Indicate what your calculated score is;
• Indicate and justifywhat your critical score is; and
• Determine if this sample average is statistically significant from the mean.