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3 years ago

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A cylinder has a base diameter of 16 feet and a height of 19 feet. What is its volume in cubic feet, to the nearest tenths place

?

1 answer:

qaws [65]3 years ago

5 0

Answer:

3820.18

Step-by-step explanation:

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Write the algebraic expression for “twice a number n decreased by seven”

kirza4 [7]

Answer:

2n - 7

Step-by-step explanation:

3 0

3 years ago

Monitors manufactured by TSI Electronics have life spans that have a normal distribution with a standard deviation of 1900 hours

lana [24]

Answer:

0.9641 = 96.41% probability that the life span of the monitor will be more than 15,579 hours.

Step-by-step explanation:

Problems of normally distributed samples are 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.

In this problem, we have that:

$\mu = 19000, \sigma = 1900$

Find the probability that the life span of the monitor will be more than 15,579 hours.

This is 1 subtracted by the pvalue of Z when X = 15579. So

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

$Z = \frac{15579 - 19000}{1900}$

$Z = -1.80$

$Z = -1.80$ has a pvalue of 0.0359

1 - 0.0359 = 0.9641

0.9641 = 96.41% probability that the life span of the monitor will be more than 15,579 hours.

5 0

3 years ago

A sample of 148 college students at a large university reports getting an average of 6.85 hours of sleep last night with a stand

nignag [31]

Answer:

70 students need to be surveyed.

Step-by-step explanation:

We have that to find our $\alpha$ level, that is the subtraction of 1 by the confidence interval divided by 2. So:

$\alpha = \frac{1 - 0.95}{2} = 0.025$

Now, we have to find z in the Ztable as such z has a pvalue of $1 - \alpha$ .

That is z with a pvalue of $1 - 0.025 = 0.975$ , so Z = 1.96.

Now, find the margin of error M as such

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

In which $\sigma$ is the standard deviation of the population and n is the size of the sample.

Assuming that the standard deviation of the above sample is a reasonable estimate of the standard deviation of sleep time at your university.

This means that $\sigma = 2.12$

How many students do you need to survey to estimate the mean sleep time of students at your university with 95% confidence and a margin of error of 0.5 hours?

n students need to be surveyed, and n is found when M = 0.5. So

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

$0.5 = 1.96\frac{2.12}{\sqrt{n}}$

$0.5\sqrt{n} = 1.96*2.12$

Multiplying by 2 on both sides:

$\sqrt{n} = 1.96*4.24$

$(\sqrt{n})^2 = (1.96*4.24)^2$

$n = 69.1$

Rounding up

70 students need to be surveyed.

3 0

3 years ago

Need help with this paper!!

Nataly_w [17]

Answer:

1. b

2. c

3. c

4. a

5. b

7 0

3 years ago

How to solve it using elimination

gregori [183]

X=3
y=5

You have to cancel out either the x values or the y values (I chose y). You multiply both equations by particular numbers so either the x values or y values can be equal to each other, as well as positive or negative to each other. I multiplied -7y by 4 and 4y by 7, and got -28y and 28y. I then canceled those out. The numbers you multiply by also affects the rest of the equations, so I ended up with 48x=4 and -35x=35. After that, you combine like terms, which results in 13x=39. You divide 13 by both sides and you end up with x=3. To find y, all you have to do is plug in the x value to one of the equations, then solve for y. I resulted in y=5.

Hope this helped ^_^

8 0

3 years ago