A Biology teacher wants to see if there is any difference in the abilities of students enrolled in biology today and those enrolled five years ago. A sample of final examination scores from students enrolled today and from students enrolled five years ago was taken. You are given the following information. Today Five Years Ago 81 85 σ 14.5 8.5 n 81 36 ​ The point estimate for the difference between the means of the two populations is

The point estimate for the difference between the means of the two populations is x1`-x2`= 81-85=-4 where x1` is the mean of the of the first population and x2` is the mean of the second population.

Step-by-step explanation:

The data given is

               Today               Five Years Ago

X`                 81                           85

σ              14.5                        8.5

n                81                          36

The point estimate for the difference between the means of the two populations is x1`-x2`= 81-85=-4 where x1` is the mean of the of the first population and x2` is the mean of the second population.

The test statistics that will be used is

Z= x1-x2/ √σ₁²/ n₁ + σ₂²/n₂

Z=  81- 85/ √14.5² /81 + 8.5² /36

z= -4/√210.25/81+ 72.25/36

z= -4/2.1454

z= -1.8644

312312

step-by-step explanation:

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.