Adriana, henry, malik, and richard each design surveys to determine the most popular way seventh graders purchase music. adriana samples the five friends sitting at her lunch table. henry samples every boy in his homeroom class. malik samples every student using an mp3 player while waiting for the bus. richard samples the first student alphabetically on the class roster from each of 12 classes. which sample is likely to produce the most valid results?

Richard's method is the best method and is likely to produce the most valid results.

Step-by-step explanation:

Given scenario is :

A survey is designed to determine the most popular way seventh graders purchase music.

Adriana samples the five friends sitting at her lunch table.

Henry samples every boy in his homeroom class.

Malik samples every student using an MP3 player while waiting for the bus.

Richard samples the first student alphabetically on the class roster from each of 12 classes.

Out of all the four students, we can see that Richard conducted his survey using a random sampling technique where every possible individual was at the probability of being chosen.

So, Richard's method is the best method and is likely to produce the most valid results.

Other students did not prefer random sampling and chose people around them for their survey. So, it is a statistical bias.

answer is a

step-by-step explanation:

d. 8

step-by-step explanation:

the given radical expression is:

we can rewrite this as:

we express as square numbers to get;

the exponents will now cancel out to give.

the correct answer is d