In order to maximize the chances that experimental groups represent the population of interest, researchers should conduct random sampling and random group assignment
<u>Explanation:</u>
The terms Random sampling and Random group assignment are greatly different in process of the sample selection. The study related to the determination of how sample participants can be drawn from the population refers to the process of Random sampling. The sample participants are subjected to a treatment by the usage of a random procedure comprises the Random group assignment.
When a researcher wants validate externally then random selection can be used. When a researcher wants to determine the effects of treatment within that group which is known as determination of internal validity then he can opt for Random group assignment.
A perfect number is a number where the sum of its divisors is equal to the number.
For example 6: 1 + 2 + 3 = 6
Another example is 28: 1 + 2 + 4 + 7 + 14 = 28
Here is a short list of perfect numbers: 6, 28, 496, 8128, <span>33550336, and the numbers get way bigger as we go on.</span>
Option A
is one way to determine the factors of 
by grouping
<em><u>Solution:</u></em>
Factoring by grouping means that you will group terms with common factors before factoring
<em><u>Given expression is:</u></em>
Group the first two terms together and then the last two terms together.
We can see that 
is common in first two terms
And 3 is common in last two terms
Factor them out
Thus option A is correct
1. -1/5>-3/5 because we have like denominators we compare the inputs by the numerators.
2. 3/4 > 5/8 the least common denominator is: 8
Rewriting as equivalent fractions with the LCD:
3/4 = 6/8 5/8 = 5/8
Comparing the numerators of the equivalent fractions we have:
6/8 > 5/8
Zinc = 7/18
Divide 4.9 by 7 = 0.7
Multiply by 18 = 12.6
The answer is 12.6 lbs of alloy. Sorry if I'm wrong
