How did railroads help define the era and benefit the nation? They united the country by making tariffs profitable for each region: North, South, and West.

They helped create one integrated economy, moving raw materials from farms in the North to factories in the South.

They were used to ship goods and crops across the nation and helped achieve unprecedented growth.

They strengthened democracy in the United States by making election results known in a timelier manner.

Use the given degree of confidence and sample data to construct a confidence interval for the population mean mu . assume that the population has a normal distribution. a laboratory tested twelve chicken eggs and found that the mean amount of cholesterol was 185 milligrams with sequals 17.6 milligrams. a confidence interval of 173.8 mgless than muless than 196.2 mg is constructed for the true mean cholesterol content of all such eggs. it was assumed that the population has a normal distribution. what confidence level does this interval represent?