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3 years ago

Suppose the test scores on an exam show a normal distribution with a mean of 82 and a standard deviation of

Mathematics

1 answer:

Zanzabum3 years ago

5 0

Answer:

a) Between 74 and 90

b) 81.86% of the scores are between 78 and 90

Step-by-step explanation:

a) According to the Empirical Rule, in a normal distribution, 95% of the data are within 2 standard deviations of the mean. Therefore, the range that 95% of the scores fall in is between 82-4(2)=74 and 82+4(2)=90.

b) The percent of scores that are between 78 and 90 is: normalcdf(lower,upper,μ,σ) = normalcdf(78,90,82,4) = 0.8185946784 ≈ 0.8186, or about 81.86% of the scores.

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A survey reported in Time magazine included the question ‘‘Do you favor a federal law requiring a 15 day waiting period to purch

galben [10]

Answer:

Step-by-step explanation:

Confidence interval for the difference in the two proportions is written as

Difference in sample proportions ± margin of error

Sample proportion, p= x/n

Where x = number of success

n = number of samples

For the men,

x = 318

n1 = 520

p1 = 318/520 = 0.61

For the women

x = 379

n2 = 460

p2 = 379/460 = 0.82

Margin of error = z√[p1(1 - p1)/n1 + p2(1 - p2)/n2]

To determine the z score, we subtract the confidence level from 100% to get α

α = 1 - 0.95 = 0.05

α/2 = 0.05/2 = 0.025

This is the area in each tail. Since we want the area in the middle, it becomes

1 - 0.025 = 0.975

The z score corresponding to the area on the z table is 1.96. Thus, confidence level of 95% is 1.96

Margin of error = 1.96 × √[0.61(1 - 0.61)/520 + 0.82(1 - 0.82)/460]

= 1.96 × √0.0004575 + 0.00032086957)

= 0.055

Confidence interval = 0.61 - 0.82 ± 0.055

= - 0.21 ± 0.055

3 0

3 years ago

Can someone answer this for me pls

lions [1.4K]

Answer:answer from math papa is b=−n+30

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3 years ago

F(x) = square root 3x+7 , g(x) = square root 3x-7<br><br> Find (f + g)(x).

Veseljchak [2.6K]

Your basically building a new equation with the two functions given to you.
(sqrt(3x + 7)) + (sqrt(3x - 7)) = 0

Then just open up the brackets and simplify further.
sqrt(3x + 7) + sqrt(3x - 7)= 0

Nothing to special really happened there, just removed the brackets. Now you move one of the radicals to the other side so you can square the whole equation.
sqrt(3x + 7) = - sqrt(3x - 7)

Then go ahead and square both sides to remove the radical.
3x + 7 = 3x - 7

Now if you kept trying to isolate x, you find that both sides will just cancel each other out and you are left with,
7 = -7

Since that statement isn't true your answer will be that there is no solution to this equation.
x ∈ Ø

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3 years ago

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for her phone service, ann pays a monthly fee offor her phone service and pays a monthly fee of $18 and she pays an additional $

trapecia [35]

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4 years ago

Isa and Jack have part-time jobs.

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If x is number of hours worked and y total pay, in y=9.5x, 9.5 is hourly rate.
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3 years ago