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m_a_m_a [10]
3 years ago
7

Someone help no websites or links plz if right will mark brainiest :)

Mathematics
1 answer:
natima [27]3 years ago
5 0

Answer:

Cos Z= 4/5

Step-by-step explanation:

Hope it helps you!

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Fourteen more than a number is eighteen.
AVprozaik [17]

Answer: 4

Step-by-step explanation:

18-14=4

3 0
3 years ago
Suppose the population of a certain city is 5289 thousand. It is expected to decrease to 4530 thousand in 50 years. Find the per
Tcecarenko [31]

Answer:

14.4% decrease

Step-by-step explanation:

Here is the formula for finding the percentage of decrease:

(starting value - final value) / starting value * 100.

So for your question,

\frac{5289-4530}{5289} =.0144\\.0144 * 100 = 14.4\\/

There was a 14.4% decrease within 50 years.

5 0
3 years ago
Simplify the following: <br><br> 0.9√86<br><br> 2√131
dimulka [17.4K]
OK 
The first one would be
8.34625

The second one would be
22.89104 

H0P3 It H3LPS :)
6 0
3 years ago
A coach for a sport picks the initial lineup of seven out of eleven players for a game. The first two are always numbers seven a
Cerrena [4.2K]

Answer:

add 11 and 7 togive you 18 and it is over 2.therefore the answer is 1/9

3 0
3 years ago
A company with a large fleet of cars wants to study the gasoline usage. They check the gasoline usage for 50 company trips chose
Nookie1986 [14]

Answer:

The 95% confidence interval is given by (25.71536 ;28.32464)

And if we need to round we can use the following excel code:

round(lower,2)

[1] 25.72

round(upper,2)

[1] 28.32

And the interval would be (25.72; 28.32)  

Step-by-step explanation:

Notation and definitions  

n=50 represent the sample size  

\bar X= 27.2 represent the sample mean  

s=5.83 represent the sample standard deviation  

m represent the margin of error  

Confidence =88% or 0.88

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".  

Calculate the critical value tc  

In order to find the critical value is important to mention that we don't know about the population standard deviation, so on this case we need to use the t distribution. Since our interval is at 88% of confidence, our significance level would be given by \alpha=1-0.88=0.12 and \alpha/2 =0.06. The degrees of freedom are given by:  

df=n-1=50-1=49  

We can find the critical values in R using the following formulas:  

qt(0.06,49)

[1] -1.582366

qt(1-0.06,49)

[1] 1.582366

The critical value tc=\pm 1.582366  

Calculate the margin of error (m)  

The margin of error for the sample mean is given by this formula:  

m=t_c \frac{s}{\sqrt{n}}  

m=1.582366 \frac{5.83}{\sqrt{50}}=14.613  

With R we can do this:

m=1.582366*(5.83/sqrt(50))

m

[1] 1.304639

Calculate the confidence interval  

The interval for the mean is given by this formula:  

\bar X \pm t_{c} \frac{s}{\sqrt{n}}  

And calculating the limits we got:  

27.02 - 1.582366 \frac{5.83}{\sqrt{50}}=25.715  

27.02 + 1.582366 \frac{5.83}{\sqrt{50}}=28.325

Using R the code is:

lower=27.02-m;lower

[1] 25.71536

upper=27.02+m;upper

[1] 28.32464

The 95% confidence interval is given by (25.71536 ;28.32464)  

And if we need to round we can use the following excel code:

round(lower,2)

[1] 25.72

round(upper,2)

[1] 28.32

And the interval would be (25.72; 28.32)  

6 0
3 years ago
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