Which statement identifies the sampling procedure used and gives a valid reason?
Researchers conducted a study on the effects of practice
time of athletes on their endurance.
To form the sample, researchers grouped the population
by sport and then randomly selected 25 athletes from
each group.
O Stratified random sampling: all subjects from each
chosen sport were sampled.
O Stratified random sampling: subjects were randomly
selected from each sport.
O Cluster sampling: all subjects from each chosen
sport were sampled.
O Cluster sampling: subjects were randomly sampled
from each sport.

While slavery was the major issue separating the North and South, it was not slavery itself that sparked the conflict. The South wanted to secede from the Union, and the North refused. While President Abraham Lincoln personally opposed slavery, he recognized that it was legal under the U.S. Constitution at the time. He also recognized that few in the North were ready to go to war to free the slaves. For Lincoln and the northern majority, preservation of the Union was the foremost goal.

answer: evaluate the objective function at each vertex to determine which - and -values, if any, maximize or minimize the function. example: find the minimum value and maximum value of the objective function f ( x , y ) = 4 x + 5 y , subject to the following constraints

step-by-step explanation: it is d