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2 years ago

Which expression is equivalent to (7-8) (78)?

Mathematics

1 answer:

Gre4nikov [31]2 years ago

8 0

-78

Step-by-step explanation:

(7-8)(78)

(-1)(78)=-78

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A student wanted to construct a 95% confidence interval for the average age of students in her statistics class. She randomly se

Darina [25.2K]

Answer: (17.42, 20.78)

Step-by-step explanation:

As per given , we have

Sample size : n= 9

$\overline{x}=19.1$ years

Population standard deviation is not given , so it follows t-distribution.

Sample standard deviation : s= 1.5 years

Confidence level : 99% or 0.99

Significance level : $\alpha= 1-0.99=0.01$

Degree of freedom : df= 8 (∵df =n-1)

Critical value : $t_c=t_{(\alpha/2,\ df)}=t_{0.005,\ 8}= 3.355$

The 99% confidence interval for the population mean would be :-

$\overline{x}\pm t_c\dfrac{s}{\sqrt{n}}$

$19.1\pm (3.355)\dfrac{1.5}{\sqrt{ 9}}\\\\=19.1\pm1.6775\\\\=(19.1-1.6775,\ 19.1+1.6775)\\\\=(17.4225,\ 20.7775)\approx(17.42,\ 20.78)$

Hence, the 99% confidence interval for the population mean is (17.42, 20.78) .

7 0

3 years ago

If a dart hits the target at random note this is an isosceles triangle what is the probability that it will land in the shaded r

enyata [817]

Multiply 12 and 3 and you will get four. four is like 1 over 4: 1/4

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3 years ago

Researchers are studying the distribution of subscribers to a certain streaming service in different populations. From a random

Katen [24]

Answer:

$CI = (0.17 - 0.27)\± 1.65\sqrt{\frac{(0.17)*(0.83) + (0.27)*(0.73)}{200}}$

Step-by-step explanation:

Given

$n = 200$

$x_1 = 34$ -- City C

$x_2 = 54$ --- City K

Required

Determine the 90% confidence interval

This is calculated using:

$CI = \bar x \± z\frac{\sigma}{\sqrt n}$

Calculating $\bar x$

$\bar x = \bar x_1 - \bar x_2$

$\bar x = \frac{x_1}{n} - \frac{x_2}{n}$

$\bar x = \frac{34}{200} - \frac{54}{200}$

$\bar x = 0.17 - 0.27$

For a 90% confidence level, the z-score is 1.65. So:

$z = 1.65$

Calculating the standard deviation $\sigma$

$\sigma = \sqrt{(\bar x_1)*(1 - \bar x_1) + (\bar x_2)*(1 - \bar x_2) }$

So:

$\sigma = \sqrt{(0.17)*(1 - 0.17) + (0.27)*(1 - 0.27) }$

$\sigma = \sqrt{(0.17)*(0.83) + (0.27)*(0.73)}$

So:

$CI = (0.17 - 0.27)\± 1.65\frac{\sqrt{(0.17)*(0.83) + (0.27)*(0.73)}}{\sqrt {200}}$

$CI = (0.17 - 0.27)\± 1.65\sqrt{\frac{(0.17)*(0.83) + (0.27)*(0.73)}{200}}$

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2 years ago

PLEASE HELP Which line has an x-intercept of -5 and a y-intercept of 3?

anygoal [31]

Answer:

the first answer or a

Step-by-step explanation:

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3 years ago

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Answer:

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Step-by-step explanation:

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3 years ago