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Sergeeva-Olga [200]

4 years ago

14

The exact vaule of cos(247.5 degrees)

1 answer:

Leni [432]4 years ago

8 0

$cos(247.5 deg)=cos( \frac{495deg}{2})
 = - \sqrt{ \frac{1+cos(495deg)}{2} } 
 = -\sqrt{ \frac{1- \frac{ \sqrt{2} }{2} }{2} } 
 = \frac{ \sqrt{2- \sqrt{2} } }{2}$

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3 years ago

A researcher surveyed 150 high school students and found that 68% played a musical insturment. What would be a reasonable range

maria [59]

Answer:

The reasonable range for the population mean is (61%, 75%).

Step-by-step explanation:

The interval estimate of a population parameter is an interval of values that consist of the values within which the true value of the parameter lies with a certain probability.

The mean of the sampling distribution of sample proportion is, $\hat p$ .

One of the best interval estimate of population proportion is the 95% confidence interval for proportion,

$CI=\hat p \pm z_{\alpha/2}\sqrt{\frac{\hat p(1-\hat p)}{n}}$

Given:

n = 150

$\hat p$ = 0.68

The critical value of <em>z</em> for 95% confidence level is:

$z_{\alpha/2}=z_{0.05/2}=z_{0.025}=1.96$

Compute the 95% confidence interval for proportion as follows:

$CI=\hat p \pm z_{\alpha/2}\sqrt{\frac{\hat p(1-\hat p)}{n}}$

$=0.68\pm1.96\sqrt{\frac{0.68(1-0.68)}{150}}\\\\=0.68\pm 0.0747\\\\=(0.6053, 0.7547)\\\\\approx (0.61, 0.75)$

Thus, the reasonable range for the population mean is (61%, 75%).

5 0

3 years ago

When StartFraction 2 x squared Over y EndFraction = StartFraction w + 2 Over 4 EndFraction is solved for w, one equation is w =

Andru [333]

Answer:

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Step-by-step explanation:

4 0

3 years ago

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Rashid [163]

Answer:

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3 years ago

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coldgirl [10]

Answer:

$\sf slope: \boxed{\bf \frac{1}{3} }$

Explanation:

$\sf slope :\dfrac{y_2-y_1}{x_2-x_1} =\dfrac{rise}{run} \ \ \ \ where \ (x_1, \ y_1) ,(x_2, \ y_2) \ are \ points$

Find slope:

$\rightarrow \sf \dfrac{x_2-x_1}{y_2-y_1}$

<em>insert values</em>

$\rightarrow \sf \dfrac{3-5}{-4-2}$

<em>simplify</em>

$\rightarrow \sf \dfrac{1}{3}$

4 0

2 years ago

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