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2 years ago

The following data represents the number of blogs that a sample of students state they follow. 12,3,10,9,0,1,8,7,3,10,19

Mathematics

1 answer:

aleksley [76]2 years ago

3 0

Standard deviation: 5.54

Step-by-step explanation:

In order to calculate the standard deviation of this dataset, we need to calculate the mean first.

The mean is given by:

$\bar{x}=\frac{1}{N}\sum x_i$

The data in this set are:

12,3,10,9,0,1,8,7,3,10,19

And the number of points is N = 11, so the mean is

$\bar x=\frac{1}{11}(12+3+10+9+0+1+8+7+3+10+19)=82$

Now we can calculate the standard deviation, given by

$\sigma = \sqrt{\frac{1}{N-1}\sum (x_i-\bar x)^2}$

Let's calculate the term $\sum (x_i-\bar x)^2$ first:

$\sum (x_i-\bar x)^2=\sum (x_i-7.46)^2=306.7$

And therefore, the standard deviation is:

$\sigma = \sqrt{\frac{1}{11-1}(306.7)}=5.54$

Learn more about mean and standard deviation:

brainly.com/question/6073431

brainly.com/question/8799684

brainly.com/question/4625002

#LearnwithBrainly

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A sample of 50 drills had a mean lifetime of 12.17 holes drilled when drilling a low-carbon steel. Assume the population standar

zmey [24]

Using the z-distribution, it is found that the 95% confidence interval for the mean lifetime of this type of drill, in holes drilled, is (10.4, 13.94).

We are given the standard deviation for the population, hence, the z-distribution is used. The parameters for the interval is:

Sample mean of $\overline{x} = 12.17$
Population standard deviation of $\sigma = 6.37$
Sample size of $n = 50$ .

The margin of error is:

$M = z\frac{\sigma}{\sqrt{n}}$

In which z is the critical value.

We have to find the critical value, which is z with a p-value of $\frac{1 + \alpha}{2}$ , in which $\alpha$ is the confidence level.

In this problem, $\alpha = 0.95$ , thus, z with a p-value of $\frac{1 + 0.95}{2} = 0.975$ , which means that it is z = 1.96.

Then:

$M = 1.96\frac{6.37}{\sqrt{50}} = 1.77$

The confidence interval is the sample mean plus/minutes the margin of error, hence:

$\overline{x} - M = 12.17 - 1.77 = 10.4$

$\overline{x} + M = 12.17 + 1.77 = 13.94$

The 95% confidence interval for the mean lifetime of this type of drill, in holes drilled, is (10.4, 13.94).

A similar problem is given at brainly.com/question/22596713

6 0

2 years ago

Describe the process for graphing the equation y =-1/2x- 1

AysviL [449]

the formula is y=mx+b

m is the slope

b is the y-intercept form

so the -1 is the y-intercept form. so you need to start at that point on the y axis. then the slope which is -1/2 comes into play. in my school we use rise/run. so from the point you marked at -1 you will go down 1 and to the right 2 points then where you stop is your next point (mark it) keep doing that. also go up the other way from the -1 point. go up 1 and to the left 2. then connect all of your points with a line. I hope this helped.

please chose this answer as brainliest

4 0

3 years ago

What is the value of x in the equation? 3x12-7 4 A) B) 1 C) 13 D)

kipiarov [429]

Answer:

TNX ME LATER again HAHA JWK

5 0

2 years ago

Estimate √53 between two numbers to the tenths place.

ZanzabumX [31]

Answer:

53 lies between 7.2² and 7.3²

Step-by-step explanation:

Estimating a root to the nearest tenth can be done a number of ways. The method shown here is to identify the tenths whose squares bracket the value of interest.

You have answered the questions of parts 1 to 3.

You are given that ...

7.2² = 51.84

7.3² = 53.29

This means 53 lies between 7.2² and 7.3², so √53 lies between 7.2 and 7.3.

53 is closer to 7.3², so √53 will be closer to 7.3 than to 7.2.

7.3 is a good estimate of √53 to the tenths place.

_____

Additional comment

For an integer n that is the sum of a perfect square (s²) and a remainder (r), the square root is between ...

s +r/(2s+1) < √n < s +r/(2s)

For n = 53 = 7² +4, this means ...

7 +4/15 < √53 < 7 +4/14

7.267 < √53 < 7.286

Either way, √53 ≈ 7.3.

The root is actually equal to the continued fraction ...

$\sqrt{n}=\sqrt{s^2+r}=s+\cfrac{r}{2s+\cfrac{r}{2s+\dots}}$

7 0

1 year ago

Any help would be great . Thank you!

vladimir1956 [14]

X = 4 and Y = 9. I did a complicated way of doing it so if u copy it it would look weird

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2 years ago