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3 years ago

PLEASE HELP URGENT 15 POINTS

Mathematics

2 answers:

juin [17]3 years ago

7 0

6/3 units

Y^2=(6+3)^2 - 6^2

adelina 88 [10]3 years ago

7 0

UT = sqrt(6^2 - 3^2)
UT = sqrt(36 - 9)
UT = sqrt(27)

y = sqrt[(9^2 + (sqrt(27))^2]
y = sqrt(81 + 27)
y = sqrt (108)
y = 6 sqrt(3)

answer is B. 6 sqrt(3) second choice

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What is the radius of a circle if it's diameter is 3m?

Sveta_85 [38]

The radius is half of the diameter so if the diameter is 3 then the radius is 1.5. ANSWER:1.5 what I did was just divide 3by 2 to get half of 3.

8 0

3 years ago

The 2008 Workplace Productivity Survey, commissioned by LexisNexis and prepared by WorldOne Research, included the question, "Ho

vitfil [10]

Answer:

Therefore, the sampling distribution of $\bar{x}$ is normal with a mean equal to 9 hours and a standard deviation of 0.7969 hours.

The 95% interval estimate of the population mean $\mu$ is

LCL = 7.431 hours to UCL = 10.569 hours

Step-by-step explanation:

Let X be the number of hours a legal professional works on a typical workday. Imagine that X is normally distributed with a known standard deviation of 12.6.

The population standard deviation is

$\sigma = 12.6 \: hours$

A sample of 250 legal professionals was surveyed, and the sample's mean response was 9 hours.

The sample size is

$n = 250$

The sample mean is

$\bar{x} = 9 \: hours$

Since the sample size is quite large then according to the central limit theorem, the sample mean is approximately normally distributed.

The population mean would be the same as the sample mean that is

$\mu = \bar{x} = 9 \: hours$

The sample standard deviation would be

$s = {\frac{\sigma}{\sqrt{n} }$

Where is the population standard deviation and n is the sample size.

$s = {\frac{12.6}{\sqrt{250} }$

$s = 0.7969 \: hours$

Therefore, the sampling distribution of $\bar{x}$ is normal with a mean equal to 9 hours and a standard deviation of 0.7969 hours.

The population mean confidence interval is given by

$\text {confidence interval} = \mu \pm MoE\\\\$

Where the margin of error is given by

$$ MoE = t_{\alpha/2}(\frac{s}{\sqrt{n} } ) $ \\\\$

Where n is the sampling size, s is the sample standard deviation and is the t-score corresponding to a 95% confidence level.

The t-score corresponding to a 95% confidence level is

Significance level = α = 1 - 0.95 = 0.05/2 = 0.025

Degree of freedom = n - 1 = 250 - 1 = 249

From the t-table at α = 0.025 and DoF = 249

t-score = 1.9695

$MoE = t_{\alpha/2}(\frac{\sigma}{\sqrt{n} } ) \\\\MoE = 1.9695\cdot \frac{12.6}{\sqrt{250} } \\\\MoE = 1.9695\cdot 0.7969\\\\MoE = 1.569\\\\$

So the required 95% confidence interval is

$\text {confidence interval} = \mu \pm MoE\\\\\text {confidence interval} = 9 \pm 1.569\\\\\text {LCI } = 9 - 1.569 = 7.431\\\\\text {UCI } = 9 + 1.569 = 10.569$

The 95% interval estimate of the population mean $\mu$ is

LCL = 7.431 hours to UCL = 10.569 hours

8 0

4 years ago

Sarah is doing research on the average age of first-year resident physicians. She wants her estimate to be accurate to within 1

WINSTONCH [101]

Answer: The number of first-year residents she must survey to be 95% confident= 263

Step-by-step explanation:

When population standard deviation ( $\sigma$ ) is known and margin of error(E) is given, then the minimum sample size (n) is given by :-

$n=(\dfrac{z^*\sigma}{E})^2$ , z* = Two-tailed critical value for the given confidence interval.

For 95% confidence level , z* = 1.96

As, $\sigma$ = 8.265, E = 1

So, $n= (\dfrac{1.96\times8.265}{1})^2 =(16.1994)^2\\\\= 262.42056036\approx263\ \ \ [\text{Rounded to the next integer}]$

Hence, the number of first-year residents she must survey to be 95% confident= 263

7 0

3 years ago

Pls help , will give brainliest answer

bija089 [108]

I know this answer!!! It’s A and C for the first one!

3 0

3 years ago

Please help with question 4A,B please<br> Thank you

mrs_skeptik [129]

<h3>Given</h3>

C(t) = 40 cm + t·(2/5 cm/s) . . . circumference of a circle vs time

dr/dt for radius r
r at t=4 seconds

<h3>Solution</h3>

The circumference and radius of a circle are related by

... C = 2πr

so the radius in terms of circumference is

... r = C/(2π)

... r(t) = (40 +0.4t)/(2π) = (1/π)(20 cm + 0.2t cm/s)

Then dr/dt is

... dr/dt = 0.2/π cm/s

And the radius at t=4 s is

... r(4) = (1/π)(20 + 0.2·4) cm

... r(4) = 20.8/π cm

4 0

3 years ago