I need help hereeeeeeee

A biology teacher wants to know which dissection his students liked best this semester, so he randomly selects eights students f

natali 33 [55]

Answers:

a) The 40 students selected to participate in the survey (8*5 = 40).
b) The population is the set of all students in his five classes combined.

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Explanation:

The teacher wants to know something about his students, so he's only focused on them and no one else. The teacher has 5 classes. Let's say each class has 40 students. That would mean 40*5 = 200 students total are taught by this bio teacher, and these 200 students make up the population. We're not considering any other student in this school since they are not in this teacher's class.

Once the population is well formed and well defined, the sample is drawn from the population. Specifically, the teacher is randomly selecting 8 people from each class. The teacher is using the stratified sample technique. Each class is a stratum, ie, a separate group. The plural of stratum is strata. Because there are 5 classes, and 8 people selected per class, this leads to an overall sample of 8*5 = 40 students. Those 40 students chosen randomly fairly represent the 200 students in the population. Therefore, this process is fairly unbiased.

Be sure not to mix stratified sampling with cluster sampling. Cluster sampling is not performed here because that would mean the teacher randomly selects say 2 classrooms (ie clusters) and samples everyone in each cluster selected. Instead, the teacher is only picking representatives from each class, as if those people were elected to office. As you can probably guess, cluster sampling can be expensive in terms of time and money, so if you need to apply a cluster sample, then it's best to make the clusters as small as possible but also make sure each cluster is reflective of the population.

5 0

3 years ago

The gcf of 42 and 70 is

Charra [1.4K]

The gcf of 42 and 70 is 14

7 0

3 years ago

Read 2 more answers

65% of what number is 78? Quick

SOVA2 [1]

Answer:

The answer is 120.

Step-by-step explanation:

7 0

3 years ago

Read 2 more answers

A bag contains 2 white marbles and 7 purple marbles. Two marbles are drawn at random. One marble is drawn and not replaced. Then

Masja [62]

A.
$\frac{7purple}{9total} * \frac{2white}{8total} \\ \frac{14}{72} \\ =0.194$
The denominator of the second number goes down one because you aren't replacing the initial marble pulled, making the amount of marbles in the bag go down, but not affecting the white count because you pulled a purple marble.
b.
$\frac{2white}{9total} * \frac{1white}{8total} \\ \frac{2}{72} \\ =0.278$
The same can be said about the denominator for this problem, but not the numerator. The numerator must go down one number as well, because you already chose one white marble, taking one of the white marbles out of the bag, leaving you with one solitary, white marble.
c.
Chance of selecting two purple marbles:
 $\frac{7purple}{9total} * \frac{6purple}{8total} \\ \frac{42}{72} \\ =0.583$
Chance of selecting two white marbles:
$\frac{2white}{9total} * \frac{1white}{8total} \\ \frac{2}{72} \\ =0.278$
Chance of selecting two purple vs. Chance of Selecting 2 white:
0.583>0.278.
It is more likely to select 2 purple marbles.

Hope this helps!

6 0

3 years ago

Read 2 more answers

What is the value of y? O A. 30° OB. 40° O C. 50° O D. 60°

Lera25 [3.4K]

<h3>Answer: B. 40</h3>

For any triangle, the three angles always add to 180

(y+10)+(2y)+(50) = 180

3y+60 = 180 ... combine like terms

3y+60-60 = 180-60 ... subtract 60 from both sides

3y = 120

3y/3 = 120/3 .... divide both sides by 3

y = 40

5 0

3 years ago