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Nesterboy [21]
4 years ago
11

Maridel wants to find out how many of her classmates plan to come to the next football game. There are 800 students in her schoo

l. She selects a sample of the population by putting the names of every student into a bag and drawing out 100 names. Which statement(s) describe her sampling method? Check all that apply. Her method will produce a biased sample. Her method will produce a valid sample. Her method will produce a random sample. Her method will produce a representative sample. Her method will produce an invalid sample.
Mathematics
2 answers:
OverLord2011 [107]4 years ago
8 0

Her method will produce a valid sample.

Her method will produce a random sample.

Her method will produce a representative sample.



VLD [36.1K]4 years ago
4 0

Answer:

2nd, 3rd and 4th options are correct.

Step-by-step explanation:

There are 800 students in her school. Maridel selects a sample of the population by putting the names of every student into a bag and drawing out 100 names.

Her sampling method is random and valid. As she has not chosen the names of students based on some order or preference, she has chosen completely random names.

So, the statements that describe her sampling method are:

2. Her method will produce a valid sample.

3. Her method will produce a random sample.

4. Her method will produce a representative sample.

You might be interested in
The time for a visitor to read health instructions on a Web site is approximately normally distributed with a mean of 10 minutes
klio [65]

Answer:

a) The mean is 10 and the variance is 0.0625.

b) 0.6826 = 68.26% probability that the mean time of the visitors is within 15 seconds of 10 minutes.

c) 10.58 minutes.

Step-by-step explanation:

To solve this question, we need to understand the normal probability distribution and the central limit theorem.

Normal Probability Distribution

Problems of normal distributions can be solved using the z-score formula.

In a set with mean \mu and standard deviation \sigma, the z-score of a measure X is given by:

Z = \frac{X - \mu}{\sigma}

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.

Central Limit Theorem

The Central Limit Theorem establishes that, for a normally distributed random variable X, with mean \mu and standard deviation \sigma, the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean \mu and standard deviation s = \frac{\sigma}{\sqrt{n}}.

For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.

Normally distributed with a mean of 10 minutes and a standard deviation of 2 minutes.

This means that \mu = 10, \sigma = 2

Suppose 64 visitors independently view the site.

This means that n = 64,  = \frac{2}{\sqrt{64}} = 0.25

a. The expected value and the variance of the mean time of the visitors.

Using the Central Limit Theorem, mean of 10 and variance of (0.25)^2 = 0.0625.

b. The probability that the mean time of the visitors is within 15 seconds of 10 minutes.

15 seconds = 15/60 = 0.25 minutes, so between 9.75 and 10.25 seconds, which is the p-value of Z when X = 10.25 subtracted by the p-value of Z when X = 9.75.

X = 10.25

Z = \frac{X - \mu}{\sigma}

By the Central Limit Theorem

Z = \frac{X - \mu}{s}

Z = \frac{10.25 - 10}{0.25}

Z = 1

Z = 1 has a p-value of 0.8413.

X = 9.75

Z = \frac{X - \mu}{s}

Z = \frac{9.75 - 10}{0.25}

Z = -1

Z = -1 has a p-value of 0.1587.

0.8413 - 0.1587 = 0.6826.

0.6826 = 68.26% probability that the mean time of the visitors is within 15 seconds of 10 minutes.

c. The value exceeded by the mean time of the visitors with probability 0.01.

The 100 - 1 = 99th percentile, which is X when Z has a p-value of 0.99, so X when Z = 2.327.

Z = \frac{X - \mu}{s}

2.327 = \frac{X - 10}{0.25}

X - 10 = 2.327*0.25

X = 10.58

So 10.58 minutes.

6 0
3 years ago
Can someone help me out with this ??
nalin [4]

Answer:

1. b > -2

2. x <= 3

Step-by-step explanation:

Question 1:

-2(b + 5) < -6

Divide both sides by -2. Remember to change the inequality sign.

b + 5 > 3

Subtract 5 from both sides.

b > -2

Question 2:

-(x - 10) >= 7

Divide both sides by -1. Remember to change the inequality sign.

x - 10 <= -7

Add 10 to both sides.

x <= 3

6 0
4 years ago
I am just completely lost and am unsure of how to approach this problem.
Anastasy [175]

Answer:

68°

Step-by-step explanation:

As BA⊥BD, so ∠ABD = 90°

also, ∠ABD = ∠CBD + ∠ABC

⇒ 90° = 4x + 52° + 8x - 10°

⇒  12x = 48°

⇒  x = 4°

now,

∠CBD = 4x + 52°

          = 4(4°) + 52°

          = 68°

5 0
3 years ago
Tammy took a five-hour flight to Denver, Colorado. She traveled
marysya [2.9K]

Answer:

388 miles in one hour.

Step-by-step explanation:

You divide 1,940 by 5.

7 0
3 years ago
Select all of the points that are solutions to the system of linear inequalities that is listed below 10x + 4y &lt; 12 8x -3y &g
liberstina [14]

Answer:

(3, -8) and (2, -10)

Step-by-step explanation:

Given

10x + 4y < 12

8x - 3y > 20

Required

Select the true coordinate points in (3, -8) (2, 5) (-5, 1) (10, 3) (2, -10)

(3, -8)

x = 3 and y = -8

10x + 4y < 12

10 * 3 + 4 * -8 < 12

30 - 32 < 12

-2 < 12 --- True

8x - 3y > 20

8 * 3 - 3 * -8> 20

24 +24> 20

48> 20 --- True

(2, 5)

x = 2 and y = 5

10x + 4y < 12

10 * 2 + 4 * 5 < 12

20 + 20 < 12

40 < 12 --- False (No need to check the other inequality)

(-5, 1)

x = -5 and y = 1

10x + 4y < 12

10 * -5 + 4 * 1 < 12

-46 < 12 --- True

8x - 3y > 20

8 * -5 - 3 * 1 > 20

-43 > 20 --- False

(10, 3)

x = 10 and y = 3

10x + 4y < 12

10 * 10 + 4 * 3 < 12

112 < 12 --- False (No need to check the other inequality)

(2, -10)

x = 2 and y = -10

10x + 4y < 12

10 * 2 + 4 * -10 < 12

-20 < 12 --- True

8x - 3y > 20

8 * 2 - 3 * -10 > 20

46 > 20 --- True

Hence, the solution to the inequalities are:

(3, -8) and (2, -10)

4 0
3 years ago
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