When Zahra runs the 400 meter dash, her finishing times are normally distributed with a mean of 84 seconds and a standard deviation of 1.5 seconds. Using the
empirical rule, what percentage of races will her finishing time be between 81 and 87
seconds?

What is the standard deviation of the following data set rounded to the nearest tenth? 3, 17, 18, 15, 12, 21, 9

Abag has more green balls than blue balls, and there is at least one blue ball. let bb represent the number of blue balls and let gg represent the number of green balls. let's compare the expressions 2b2b and b + gb+g. which statement is correct? choose 1

It is saturday morning and jeremy has discovered he has a leak coming from the water heater in his attic. since plumbers charge extra to come out on the weekends, jeremy is planning to use buckets to catch the dripping water. he places a bucket under the drip and steps outside to walk the dog. in half an hour the bucket is 1/5 of the way full. what is the rate at which the water is leaking per hour?