A normal population has the mean of 20 and the variance of 100. A random sample of size is selected. (a) Find the standard deviation of the sample mean. (b) How large must the sample be if you want to halve the standard deviation

x+14

step-by-step explanation:

4444444444444 i think

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.