The products that a company is exporting in the United States have an average of 3 weeks lead time and a standard deviation of 0.5 week. Seven products are measured and assumed to be normally...

The products that a company is exporting in the United States have an average of 3 weeks lead time and a standard deviation of 0.5 week. Seven products are measured and assumed to be normally distributed, what percentage of the products have shorter lead time than 2.8 weeks?