Suppose the company decided to allow the sales representatives to choose whether to participate in the field-training program or to opt out. There are 400 who have chosen to participate in the field-training program and 600 who have opted out of the program. How might the self-selection process affect the statistical validity of the comparison of the change in the proportion of sales orders from new stores? Support your answer with a specific example.

2. angles qrt and qst both measures 156 degrees.

step-by-step explanation:  

we have been given a diagram of a circle and we are told that measure of arc qvt is 156 degrees.  

we can see from our given diagram that angle qrt and angle qst subtends to arc qvt.

since we know that angles subtended by the same arc at the circumference are always equal.

by angle subtended by same arc theorem, measure of angle qrt and angle qst will be equal to the measure of arc qvt.

therefore, angles qrt and qst both measures 156 degrees and 2nd statement is the correct choice.