What are the advantages to using exponential notation?

Describe in detail how you would construct a 95% confidence interval for a set of 30 data points whose mean is 20 and population standard deviation is 3. be sure to show that you know the formula and how to plug into it. also, clearly state the margin of error.

Adepartment store purchases screen-printed t-shirts at a cost of $5 per shirt. they mark up the price 150% (making the selling price 250% of the store's purchase price) and put them on the sales floor. every month that a t-shirt doesn't sell, the store reduces the selling price by 25%.

Savannah is painting a striped background for a mural on a wall that is 1515 yards long. she wants a total of 9696 stripes that are all the same width. which calculation should savannah use to decide how wide to make each stripe?