Circle D is centered at (-3, 3) with a radius of 5 and circle E is centered at (3,-3) with a radiu

Elza [17]

What’s the question ?

4 0

3 years ago

g A programmer plans to develop a new software system. In planning for the operating system that he will use, he needs to estim

kipiarov [429]

Answer:

a) n= 1045 computers

b) n= 442 computers

c) A. Yes, using the additional survey information from part (b) dramatically reduces the sample size.

Step-by-step explanation:

Hello!

The variable of interest is

X: Number of computers that use the new operating system.

You need to find the best sample size to take so that the proportion of computers that use the new operating system can be estimated with a 99% CI and a margin of error no greater than 4%.

The confidence interval for the population proportion is:

p' ± $Z_{1-\alpha /2}$ * $\sqrt{\frac{p'(1-p')}{n} }$

$Z_{1-\alpha /2}= Z_{0.995}= 2.586$

a) In this item there is no known value for the sample proportion (p') when something like this happens, you have to assume the "worst-case scenario" that is, that the proportion of success and failure of the trial are the same, i.e. p'=q'=0.5

The margin of error of the interval is:

d= $Z_{1-\alpha /2}$ * $\sqrt{\frac{p'(1-p')}{n} }$

$\frac{d}{Z_{1-\alpha /2}} = \sqrt{\frac{p'(1-p)}{n} }$

$(\frac{d}{Z_{1-\alpha /2}})^2 = \frac{p'(1-p')}{n}$

$n * (\frac{d}{Z_{1-\alpha /2}})^2 = p'(1-p')$

$n= [p'(1-p')]*(\frac{Z_{1-\alpha /2}}{d} )^2$

$n=[0.5(1-0.5)]*(\frac{2.586}{0.04} )^2= 1044.9056$

n= 1045 computers

b) This time there is a known value for the sample proportion: p'= 0.88, using the same confidence level and required margin of error:

$n= [p'(1-p')]*(\frac{Z_{1-\alpha /2}}{d} )^2$

$n= [0.88*0.12]*(\frac{{2.586}}{0.04})^2= 441.3681$

n= 442 computers

c) The additional information in part b affected the required sample size, it was drastically decreased in comparison with the sample size calculated in a).

I hope it helps!

4 0

4 years ago

20x+20-4-15x=96-32 solution??

svetoff [14.1K]

20x+20-4-15x=96-32

(next:subtract 96-32)

20x+20-4-15x=64

(next: then combine like terms)

5x+16=64

(next: subtract 16 from 64)

5x=48

(next: divide 48/5)

x=9.6

8 0

3 years ago

Read 2 more answers

31 POINTS PLEASE HELP MEEEEEEE :DD

vazorg [7]

Answer:

8.25y - 14

Step-by-step explanation:

4(1.75y - 3.5) + 1.25y

Distribute;

7y - 14 + 1.25y

Combine like terms;

8.25y - 14

7 0

3 years ago

Thickness measurements of ancient prehistoric Native American pot shards discovered in a Hopi village are approximately normally

Svetradugi [14.3K]

Answer:

a) 0.0985 = 9.85% probability that the thickness is less than 3.0 mm.

b) 0.0582 = 5.82% probability that the thickness is more than 7.0 mm.

c) 0.8433 = 84.33% probability that the thickness is between 3.0 mm and 7.0 mm.

Step-by-step explanation:

Normal Probability Distribution:

Problems of normal distributions can be solved using the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the zscore of a measure X is given by:

$Z = \frac{X - \mu}{\sigma}$

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

Normally distributed, with a mean of 4.8 millimeters (mm) and a standard deviation of 1.4 mm.

This means that $\mu = 4.8, \sigma = 1.4$