Li designed a survey to determine how comfortable students at her middle school are with fractions. there are 600 students in her middle school. the students are equally distributed among grade levels. she selected a sample of 28 students in her first-period class. which best explains li’s sample?
a. random and biased
b. random and unbiased
c. nonrandom and biased
d. nonrandom and unbiased

C. nonrandom and biased

Step-by-step explanation:

In random sampling, there should be no pattern when designing a sample, but Li selected a sample in her first-period class. This means that Li's sample is not random.

Since 28 is too smaller than 600, the rest of the students can have different thinking from the her first -period class students. Therefore the sample must be biased.  

Therefore, option C is correct the sample explained by Li is non random and biased.

d

step-by-step explanation:

hello and welcome!

so, when we see the words "proportional" along with a table, we need to know that we're looking numbers that divide by the same thing.

looking at this table, we simply have to do a trial and error, and divide to see which numbers have the same quotient. if you look at choice a & c, they both have equal quotients for three of the numbers, with one exception, so those can't be the answer. looking at b, there is no similarity, so that can't be it. then, we see d; if you divide all the numbers in the table, you'll see that they all divide by two, which is a proportional relationship, and our answer!

also, always remember that the x will always be the number that goes into y, and somewhere behind this table, is a formula. for this specific table, the formula would be:

since our x-value is being divided by two to get the y-value. and if they were to ask for more numbers in the series, this is the formula you would use to find them.

answer: check all that apply, where the options?

step-by-step explanation: