A researcher would like to compare the effectiveness of two different methods for teaching third-grade mathematics. One group of students is assigned to Dr. Tang's class using method I and another group is assigned to Dr. Washington's class using method II. At the end of the school year, each child is given a standardized mathematics achievement test and the two groups of scores are compared. What variable is confounded with the key variable of interest?

On the way home from visiting his family, vincent’s plane cruised at an altitude of 3.2 × 10^4 feet. he had heard that a man named felix baumgartner skydived from an altitude of 1.28 × 10^5 feet. vincent wants to know how much higher felix went on his skydiving trip. question 1 you have already seen how adding numbers works in either scientific notation or standard notation. but can you subtract numbers in scientific notation and get the same results as subtracting in standard notation? to find out, first solve vincent’s problem in standard notation. part a write the cruising altitude of vincent’s plane in standard notation.