Dr. Tanaka is an educational psychologist interested in students’ attitudes toward science and the effect of those attitudes on performance on standardized tests. He chooses his local school district to study. There are 15 high schools, and he randomly chooses five. Then, of the 2,500 students in each of those five schools, he randomly recruits 250 students. This is an example of which of the following sampling techniques?
1. Snowball sample
2. systemaic sample
3. multistage sample
4. cluster sample

Consider the reaction 2x2y2+z2⇌2x2y2z which has a rate law of rate= k[x2y2][z2] select a possible mechanism for the reaction.

The avenues in a particular city run north to south and are numbered consecutively with 1st avenue at the western border of the city. the streets in the city run east to west and are numbered consecutively with 1st street at the southern border of the city. for a festival, the city is not allowing cars to park in a rectangular region bordered by 5th avenue to the west. 9th avenue to the east, 4th street to the south, and 6th street to the north. if x is the avenue number and yis the street number, which of the following systems describes the region in which cars are not allowed to park? 5th ave 9th ave

Solving systems of linear equations: tables represent two linear functions in a systemöwhat is the solution to this system? 0 (10)0 (1.6)0 18,26)0 18-22)