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3 years ago

38" points please help

1 answer:

7 0

1. The question is incomplete

2. Answer=D

3. Answer=B

LCM of 24 and 60=120

120seconds=2minutes

4. Answer=D

4.5 miles x miles
_________= _________
15 mins 75 minutes

cross multiply
15x=337.5
divide both sides by 15
x=22.5

5. Honestly, the number of weekdays per month varies...

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A manufacturer reported a sample mean = 22.0 g and a sample standard deviation = 2.5 g based on a sample of 20 of their products

tester [92]

Answer:

$n=(\frac{1.640(2.5)}{2})^2 =4.2 \approx 5$

So the answer for this case would be n=5 rounded up to the nearest integer

Step-by-step explanation:

Previous concepts

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

$\bar X=22$ represent the sample mean

$\mu$ population mean (variable of interest)

s=2.5 represent the sample standard deviation

n represent the sample size

ME = 2 represent the margin of error accepted

Solution to the problem

The confidence interval for the mean is given by the following formula:

$\bar X \pm t_{\alpha/2}\frac{s}{\sqrt{n}}$ (1)

The margin of error is given by this formula:

$ME=z_{\alpha/2}\frac{\sigma}{\sqrt{n}}$ (2)

And on this case we have that ME =2 and we are interested in order to find the value of n, if we solve n from equation (2) we got:

$n=(\frac{z_{\alpha/2} s}{ME})^2$ (3)

We can use as estimator for the population deviation the sample deviation $\hat \sigma = s$

The critical value for 90% of confidence interval now can be founded using the normal distribution. And in excel we can use this formla to find it:"=-NORM.INV(0.05;0;1)", and we got $z_{\alpha/2}=1.640$ , replacing into formula (3) we got:

$n=(\frac{1.640(2.5)}{2})^2 =4.2 \approx 5$

So the answer for this case would be n=5 rounded up to the nearest integer

6 0

3 years ago

Rewrite 7.25 as a mixed number in lowest terms. 7 25/100 7 2/5 7 1/5 7 1/4

Galina-37 [17]

7.25 = 7 and 25/100 = 7 and 1/4

4 0

3 years ago

Read 2 more answers

The sum of three consecutive odd numbers is one hundred fifty-nine

xeze [42]

First remember that sum means to add. now think about the equation. we need to find 3 numbers that equal 159 when added together. And they are all consecutive odd numbers. so let's call the first number X. the second number would be X+2 since we have to jump over 1 even number. The third number would be X+4 since we have to jump over 2 even numbers. so now an equation to represent this would be X+(X+2)+(X+4)=159. Add like terms, and remember order of operations. if you need help getting the answers leave me a comment.

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3 years ago

The cost of a car rental is $35 per day plus 21 cents per mile. You are on a daily budget of $98. Write and solve an inequalit

erma4kov [3.2K]

Let x = mileage
98 >= 35 + .21x
Solving for x:
98 >= 35 + .21x
63 >= .21x
300 >= x
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This says that if the total mileage is 300 miles or less he will be within his budget.

4 0

3 years ago

the average rate of change of the function f(x) on the interval -3≤x≤3 is -2.5. If (-3)=14 then which of the following is the va

oksian1 [2.3K]

The average rate of change of f(x) on -3 ≤ x ≤ 3 is given to be

(f (3) - f (-3)) / (3 - (-3)) = -2.5

If f (-3) = 14, then

(f (3) - 14) / (3 + 3) = -2.5

(f (3) - 14) / 6 = -2.5

f (3) - 14 = -15

f (3) = -1

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3 years ago