The length of a school running track is measured and given as 400m. Calculate the percentage error if the length is measured to the nearest 10m

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.

You dug a hole that was 8 feet deep. after taking a short break, you dug down 3 more feet in the same hole. when finished digging, a tractor accidentally filled the hole with 4 feet of dirt. how deep is your hole now?

Abag contains pieces of paper numbered from 5 to 9. a piece of paper is drawn at random. what is the theoretical probability of drawing a number less than 8?