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krek1111 [17]
3 years ago
9

Evaluate the expression for b=5. 4b2

Mathematics
2 answers:
Galina-37 [17]3 years ago
5 0

Step-by-step explanation:

When b = 5,

4b² = 4(5)² = 4 * 5 * 5 = 100.

pishuonlain [190]3 years ago
4 0

Answer:

100 is the right answer.

Step-by-step explanation:

Given that b=5

4b² = 4(5)² = 4×25 = 100

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What is the slope of the following graph? (write your answer as a fraction unless divided by 1. Do not use spaces in your answer
alexira [117]

The slope of the graph is 4/5

<h3>How to determine the slope</h3>

Using the formula

Slope = Δ y-axis / Δ x- axis

y2 = -4

y1 = 0

x2 = -5

x1 = 0

Slope = \frac{y2 - y1}{x2 - x1}

Substitute the values into the formula

<em>Slope = </em>\frac{-4 - 0}{- 5 - 0}

Slope = \frac{-4}{-5}

Slope = \frac{4}{5}

Therefore, the slope of the graph is 4/5

Learn more about slope here:

brainly.com/question/3493733

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5 0
2 years ago
In a random sample of 80 teenagers, the average number of texts handled in a day is 50. The 96% confidence interval for the mean
Nastasia [14]

Answer:

a) \bar X =\frac{46+54}{2}=50

And the margin of error is given by:

ME= \frac{54-46}{2}= 4

The confidence level is 0.96 and the significance level is \alpha=1-0.96=0.04 and the value of \alpha/2 =0.02 and the margin of error is given by:

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

We can calculate the critical value and we got:

z_{\alpha/2} = 2.05

And if we solve for the deviation like this:

\sigma = ME * \frac{\sqrt{n}}{z_{\alpha/2}}

And replacing we got:

\sigma =4 *\frac{\sqrt{80}}{2.05} =17.45

b) ME=z_{\alpha/2}\frac{\sigma}{\sqrt{n}}=2.05 *\frac{17.45}{\sqrt{160}}=2.828

And as we can see that the margin of error would be lower than the original value of 4, the margin of error would be reduced by a factor \sqrt{2}

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 represent the sample mean  

\mu population mean (variable of interest)  

\sigma represent the population standard deviation  

n=80 represent the sample size  

Solution to the problem

Part a

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

\bar X \pm z_{\alpha/2}\frac{\sigma}{\sqrt{n}} (1)  

For this case we can calculate the mean like this:

\bar X =\frac{46+54}{2}=50

And the margin of error is given by:

ME= \frac{54-46}{2}= 4

The confidence level is 0.96 and the significance level is \alpha=1-0.96=0.04 and the value of \alpha/2 =0.02 and the margin of error is given by:

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

We can calculate the critical value and we got:

z_{\alpha/2} = 2.05

And if we solve for the deviation like this:

\sigma = ME * \frac{\sqrt{n}}{z_{\alpha/2}}

And replacing we got:

\sigma =4 *\frac{\sqrt{80}}{2.05} =17.45

Part b

For this case is the sample size is doubled the margin of error would be:

ME=z_{\alpha/2}\frac{\sigma}{\sqrt{n}}=2.05 *\frac{17.45}{\sqrt{160}}=2.828

And as we can see that the margin of error would be lower than the original value of 4, the margin of error would be reduced by a factor \sqrt{2}

5 0
3 years ago
Noreen made 8 and 2/3 cups of snack mix for a party. Her uest ate 3/4 of the mix. How much snack mix did her guest eat?
vova2212 [387]
1)8÷2*3=12(cups)
2)12÷3*4=16(mix)
4 0
4 years ago
At the newest animated movie, for every 999 children, there are 444 adults. There are a total of 393939 children and adults at t
bogdanovich [222]

27 children at the movie


4 0
3 years ago
Which type of angle pair are
zavuch27 [327]
Thank u for posting a picture!
And I believe that it would be vertical because they are the same and they r across from each other and share the same point of S
Hope this helps have a nice day!!
8 0
3 years ago
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