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You want to estimate the number of students in your middle school school who buy school lunch. Which sample is unbiased?

Nezavi [6.7K]

A biased example: Asking students who are in line to buy lunch

An unbiased example: Asking students who are leaving/going to lunch(NOT buying lunch).

But in this case, the answer choices can be... confusing.
Don't panic! You're given numbers and, of course, your use of logic.

Answer choice A: 100 students grades 6-8
Answer choice B: 20-30 students any one grade
Answer choice C: 5 students
Answer choice D: 50 students grade 8

An unbiased example would be to choose students from any grade. So we can eliminate choices B and D.

Now, the question wants to estimate how many people at your middle school buy lunch. This includes the whole entire school, and if you are going to be asking people, you aren't just going to assume that if 5 people out of 5 people you asked bought lunch, the whole school buys lunch.

So, to eliminate all bias and/or error by prediction, answer choice A, the most number of students, is your answer.

6 0

3 years ago

What is the slope line ?

sweet-ann [11.9K]

Answer:

-3.....

have a nice day

3 0

3 years ago

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16x+4(x-5) how do I solve this.?

Nadusha1986 [10]

Answer:20x-20

16x+4(x-5)

4(x-5)=4x-20

16x+4x

20x-20

8 0

3 years ago

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Using the answers from z^4=16 determine the solutions of the equation (x+1)^4=16(x-1)^4

Artemon [7]

i hope i have been useful buddy.

good luck ♥️♥️♥️♥️♥️.

4 0

3 years ago

If a student randomly guesses at 20 multiple-choice questions, find the probability that the student gets exactly four correct.

ad-work [718]

Answer:

Probability = 0.190

Step-by-step explanation:

Given:

Number of questions, 'n' = 20

Each question has four choices.

Let event of choosing correct answer be success and its probability be represented by 'p'.

Therefore, event of choosing wrong answer is failure and its probability be represented by 'q'.

Now, probability of success is choosing one correct answer out of 4 options. So, $p=\frac{1}{4}=0.25$

Now, 'p' and 'q' are complements of each other. Therefore,

$q=1-p=1-0.25=0.75$

Now, we need 4 successes. Therefore, $x=4$

Using Bernoulli's theorem to find 'x' successes from 'n' questions, we get:

$P(x)=_{x}^{n}\textrm{C}p^xq^{n-x}$

Plug in 4 for 'x', 20 for 'n', 0.25 for 'p' and 0.75 for 'q'. Solve.

$P(4)=_{4}^{20}\textrm{C}(0.25)^4(0.75)^{20-4}\\P(4)=_{4}^{20}\textrm{C}(0.25)^4(0.75)^{16}\\P(4)=4845\times (0.25)^4\times (0.65)^{16}\\\\P(4)=0.1896\approx0.190$

Therefore, the probability of getting 4 correct answers out of 20 questions is 0.190.

6 0

3 years ago