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3 years ago

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It has been reported that 48% of teenagers play video games on their phones. A random sample of 60 teenages is drawn. Find the p

robability that the proportion of teenagers in the sample who play videos games on their phone is less than 0.489 .

1 answer:

Ivanshal [37]3 years ago

3 0

Answer:

skakaaja

Step-by-step explanation:

aamnanananan

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Ella grew 3 over 4 of an inch last year. Ben grew 2 over 3 of an inch last year. How much more did Ella grow than Ben last year?

IrinaK [193]

Answer:

Ella grew $\frac{1}{12}$ of an inch more

Step-by-step explanation:

For this problem, you want to subtract Ben's growth from Ella's.

This expression would be $\frac{3}{4}$ - $\frac{2}{3}$ .

To work these out, they must have the same denominator (which should be the lowest common multiple or LCM).

In this case, the LCM is 12, so you want to multiply each side so the denominator is 12. This means the first fraction should be multiplied by $\frac{3}{3}$ and the second by $\frac{4}{4}$ .

This makes the expression $\frac{9}{12}$ - $\frac{8}{12}$ , which equals $\frac{1}{12}$ .

**This content involves adding and subtracting fractions, which you may want to revise. I'm always happy to help!

7 0

3 years ago

I’m confused on this one

GenaCL600 [577]

The slope of CD is

$m = \dfrac{6 - -4}{2 - 0} = 5$

The slope of the perpendicular bisector is the negative reciprocal,

$n = -1/m = - \dfrac 1 5$

The perpendicular bisector passes through M, the midpoint of CD

M =( (0+2)/2, (-4 + 6)/2) = (1, -1)

So point slope form for the perpendicular bisector is

$y - -1 = - \frac 1 5(x - 1)$

Solving for y gives slope intercept form.

$y = - \frac 1 5 x - \frac 4 5$

Not sure how to type that without spaces; we didn't have online homework back then.

Answer: y=(-1/5)x-4/5

3 0

3 years ago

Samuel spends a winter day recording the temperature once every three hours for science class. At 9 am, the temperature was -14.

nataly862011 [7]

Answer:

The temperature at 9 am = -14.7°F

Between 9am and 12 pm = -14.7 + 17.8 = 3.1°F

Between 12pm and 3 pm = 3.1+5.1 = 8.2°

Between 3pm and 6 pm = 8.2-14.5 = -6.3°F

6 0

3 years ago

A random sample of 5120 permanent dwellings on an entire reservation showed that 1627 were traditional hogans.

krek1111 [17]

Answer:

a) $\hat p=\frac{1627}{5120}=0.3178$

b)The 99% confidence interval would be given by (0.301;0.355)

Step-by-step explanation:

1) Notation and definitions

$X=1627$ number of permanent dwellings on the entire reservation that are traditional hogans.

$n=5120$ random sample taken

$\hat p=\frac{1627}{5120}=0.318$ estimated proportion of permanent dwellings on the entire reservation that are traditional hogans.

$p$ true population proportion of permanent dwellings on the entire reservation that are traditional hogans.

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

The population proportion have the following distribution

$p \sim N(p,\sqrt{\frac{\hat p(1-\hat p)}{n}})$

Part a

The point of estimate for p=the proportion of all permanent dwellings on the entire reservation that are traditional hogans is given by:

$\hat p=\frac{1627}{5120}=0.3178$

Part b

In order to find the critical value we need to take in count that we are finding the interval for a proportion, so on this case we need to use the z distribution. Since our interval is at 99% of confidence, our significance level would be given by $\alpha=1-0.99=0.01$ and $\alpha/2 =0.005$ . And the critical value would be given by:

$z_{\alpha/2}=-2.58, z_{1-\alpha/2}=2.58$

The confidence interval for the mean is given by the following formula:

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

If we replace the values obtained we got:

$0.318 - 2.58\sqrt{\frac{0.318(1-0.318)}{5120}}=0.301$

$0.318 + 2.58\sqrt{\frac{0.318(1-0.318)}{5120}}=0.335$

The 99% confidence interval would be given by (0.301;0.355)

8 0

3 years ago

Which expression is equivalent to 2x^5 + 4x^4 - 5x^5 - (3x^4 - 8x^5)

Naddika [18.5K]

One that could be close is Letter B?

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3 years ago