Aprofessor conducts an experiment that investigates the effects of a new statistics cd on student understanding. his one statistics class is used for the sample. he divides the roster into two halves and uses each half as a group. one group receives the cd and the other does not receive the cd. each group consists of 10 students. observations of student classroom engagement are rated by the professor, according to an engagement scale. how could this study be improved? a. randomly assign the students to the two different groups. b. repeat the study again, when a larger sample size can be derived. c. use an instrument that measures student understanding. d. ask another professor to make and rate observations, as well.

Option C. Use an instrument that measures student understanding.

Step-by-step explanation:

Thinking process:

The basis of the experiment is to measure student's understanding. Therefore, this is the primary focus of the experiment. In the test, there is an observation of the students by the professor. At the moment, there is no quantitative analysis to measure the student's understanding from the CD distribution. Thus, another method is needed to ensure the validity of the results. In this case, an instrument that measures student's understanding is needed.

u = -(6/7)w

step-by-step explanation:

place all values with 'u' on one side of the equation.

4u + 8w = - 3u + 2w

4u + 3u = 2w - 8w

further simplify the equation by solving the addition and subtraction.

7u = - 6w

make 'u' the independent variable by placing its co-efficient on the right-hand side.

u = - (6/7)w

c. 27 units.

step-by-step explanation:

we are told that in circle a, ∠bae ≅ ∠dae.

we can see from our given diagram that in and ;

, as these are radii of our given circle.

therefore, by sas congruence postulate.

hence, side be will be equal to side de as corresponding parts of congruent triangles are congruent. so we can set an equation to find the value of x as:

now let us substitute x=17 in the expression for the length of be.

therefore, length of be will be 27 units and option c is the correct choice.