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alexandr402 [8]
3 years ago
9

A school has two kindergarten classes. There are 21 children in Ms. Toodle's kindergarten class. Of these, 17 are "pre-readers"

children on the verge of reading. There are 19 children in Mr. Grimace's kindergarten class. Of these, 13 are pre-readers. Using the plus four confidence interval method, a 90% confidence interval for the difference in proportions of children in these classes that are pre-readers is -0.104 to 0.336.
1. Which of the following statements is correct?
a. This confidence interval is not reliable because the samples are so small.
b. This confidence interval is of no use because it contains 0, the value of no difference between classes.
c. This confidence interal is reasonable because the sample sizes are both at least 5.
d. This confidence interval is not reliable because these samples cannot be viewed as simple random samples taken from a larger population
Mathematics
1 answer:
pav-90 [236]3 years ago
3 0

Answer:

The correct answer is option (d).

Step-by-step explanation:

From the given example, the statement that is correct is, this confidence interval is not reliable because these samples cannot be viewed as simple random samples taken from a larger population.

This is because, In this scenario or setup, all the students are already part of the data. This is not a sample from a l population that is larger, but probably, the population itself.

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Translate the expression into a word phrase. k + 12 A. a number less than 12 B. 12 more than a number C. the product of a number
Burka [1]
The answer is b) 12 more than a number

when you use the word "more than" it means addition. when you use the word "less than" it means subtraction. when you use the word "product of" it means multiplication. when you use "quotient of" it mean division.

hope that helps, God bless! <span />
8 0
3 years ago
2. The path of a high diver is given by y = + (2x2 – 9x – 56), where y is the height of the diver
timofeeve [1]

Answer:

The diver will be 8 feet from the end of the board when he hits the water.

Step-by-step explanation:

The diver hits the water when y = 0.

To find the distance, we have to find the values of x when y = 0.

Solving a quadratic equation:

Given a second order polynomial expressed by the following equation:

ax^{2} + bx + c, a\neq0.

This polynomial has roots x_{1}, x_{2} such that ax^{2} + bx + c = (x - x_{1})*(x - x_{2}), given by the following formulas:

x_{1} = \frac{-b + \sqrt{\bigtriangleup}}{2*a}

x_{2} = \frac{-b - \sqrt{\bigtriangleup}}{2*a}

\bigtriangleup = b^{2} - 4ac

In this problem, we have that:

y = 2x^{2} - 9x - 56

2x^{2} - 9x - 56 = 0

So

a = 2, b = -9, c = -56

Then

\bigtriangleup = b^{2} - 4ac = (-9)^{2} - 4*2(-56) = 529

x_{1} = \frac{-(-9) + \sqrt{529}}{2*2} = 8

x_{2} = \frac{-(-9) - \sqrt{529}}{2*2} = -3.5

It is a horizontal distance, so the answer is a positive value.

The diver will be 8 feet from the end of the board when he hits the water.

7 0
3 years ago
In a certain year, when she was a high school senior, Idonna scored 671 on the mathematics part of the SAT. The distribution of
goldfiish [28.3K]

Answer:

Idonna's standardized score is 1.41.

Jonathan's standardized score is 0.55.

A.) Idonna's score is higher than Jonathan's

Step-by-step explanation:

Z-score:

In a set with mean \mu and standard deviation \sigma, the zscore 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 pvalue, we get the probability that the value of the measure is greater than X.

Idonna scored 671 on the mathematics part of the SAT. The distribution of SAT math scores in that year was Normal with mean 509 and standard deviation 115.

This means that her standardized score is Z when X = 671, \mu = 509, \sigma = 115. So

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

Z = \frac{671 - 509}{115}

Z = 1.41

Idonna's standardized score is 1.41.

Jonathan took the ACT and scored 24 on the mathematics portion. ACT math scores for the same year were Normally distributed with mean 21.1 and standard deviation 5.3 .

This means that his standardized score is Z when X = 24, \mu = 21.1, \sigma = 5.3

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

Z = \frac{24 - 21.1}{5.3}

Z = 0.55

Jonathan's standardized score is 0.55.

Due to the higher z-score, Iddona's has a higher score.

5 0
2 years ago
Determine for each number whether it is a rational number or irrational number
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Picture is too blurry man.
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