Atotal of 9 cycles have been observed during a time study. the mean for the largest element time = 0.80 min, and the corresponding sample standard deviation s = 0.15 min, which was also the largest. if the analyst wants to be 95% confident that the mean of the sample was within +/- 10% of the true mean, how many more observations should be taken?

Only one, more should be taken.

Step-by-step explanation:

See the attached file please.

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.