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

Factor p 2 + 18p + 32. (p+ 4)(p + 8) (p + 2)p+ 16) (p + 16)2

What other information do you need to prove triangle dac=bca by asa

At the olympic games, many events have several rounds of competition. one of these events is the men's 100-meter backstroke. the upper dot plot shows the times (in seconds) of the top 8 finishers in the final round of the 2012 olympics. the lower dot plot shows the times of the same 8 swimmers, but in the semifinal round. which pieces of information can be gathered from these dot plots? (remember that lower swim times are faster.) choose all answers that apply: a: the swimmers had faster times on average in the final round. b: the times in the final round vary noticeably more than the times in the semifinal round. c: none of the above.