The manager of an online shop wants to determine whether the mean length of calling time of its customers is significantly less than 9 minutes. A random sample of 28 customers was taken. The average length of calling time in the sample was 8.1 minutes with a standard deviation of 2.9 minutes. At a 0.05 level of significance, it can be concluded that the mean of the population is:

Step-by-step explanation:

1

step-by-step explanation:

it's the only multiple of both and the least

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.