(-2,3). When rotating a point 90 degrees counterclockwise about the origin our point A(x,y) becomes A'(-y,x).
Answer: 271
Step-by-step explanation:

The proportion of buses traveling more than 900 miles would be 0.0485; multiply this by the total number of buses and you will have your answer.
We find the z-score associated with 900 miles:
z = (X - μ)/σ = (900-830.11)/42.19 = 1.66
Using a z-table (http://www.z-table.com) we see that the area under the curve to the left of this, less than this, is 0.9515. This means that the area under the curve to the right of this, greater than this, would be 1-0.9515 = 0.0485.
Answer:
To find the mean: Multiply midpoints by frequencies, add the subtotals and divide by the total of the frequencies.
Step-by-step explanation:
Put the results in numerical order (in a frequency table this will already be done)
Count the total amount of results and add one.
Divide this by 2 to find the the position of the middle result.
Find the middle result in the numerically ordered list or frequency table.