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3 years ago

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Sixty-eight percent of adults in a certain country believe that life on other planets is plausible. You randomly select five adu

lts and ask them whether they believe that life on other planets is plausible. The random variable represents the number of adults who believe that life on other planets is plausible. Find the mean, variance, and standard deviation of the binomial distribution for the random variable. Interpret the results.

1 answer:

Pavlova-9 [17]3 years ago

3 0

Answer:

Mean = 3.4

Variance = 1.088

Standard deviation = 1.0431

Step-by-step explanation:

$P=0.68\\ \\N=5$

The mean of a binomial distribution with parameters N (the number of trials) and p (the probability of success for each trial) is $m=N\cdot p$

Thus,

$m=5\cdot 0.68=3.4$

The variance of the binomial distribution is $s^2=Np(1-p)$ , where $s^2$ is the variance of the binomial distribution, so

$s^2=5\cdot 0.68\cdot (1-0.68)=3.4\cdot 0.32=1.088$

The standard deviation $s$ is the square root of the variance $s^2,$ so

$s=\sqrt{1.088}\approx 1.0431$

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Mr.Baker is making a box using all of a 48-inch strip of oak. the box will be 14 inches wide. how long will the box be?

blsea [12.9K]

The length of the box made by Mr. Baker is 10-inch

Mr. Baker has strip of 48- inch long oak, by this strip he is making the rectangle box of width 14-inch.

<h3>What is a rectangle?</h3>

The rectangle is 4 sided geometric shapes whose opposites are equal in lengths and all angles are about 90°.

As Mr. Baker has a strip that is 48-inch long and he made a rectangle box with it.

The width of the box = 14 inches
now the length of the box = (total length of the strip - 2* width of the box)/2
⇒ length of the box = (48 - 2*14)/2
⇒ length of the box = 10 inches

Thus the Mr. Baker made the box which is 10 inches long.

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2 years ago

According to the National Bridge Inspection Standard (NBIS), public bridges over 20 feet in length must be inspected and rated e

slamgirl [31]

Answer:

1.80% probability that in a random sample of 12 major Denver bridges, at least 4 will have an inspection rating of 4 or below in 2020.

Step-by-step explanation:

For each bridge, there are only two possible outcomes. Either it has rating of 4 or below, or it does not. The probability of a bridge being rated 4 or below is independent from other bridges. So we use the binomial probability distribution to solve this problem.

Binomial probability distribution

The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

In which $C_{n,x}$ is the number of different combinations of x objects from a set of n elements, given by the following formula.

$C_{n,x} = \frac{n!}{x!(n-x)!}$

And p is the probability of X happening.

For the year 2020, the engineers forecast that 9% of all major Denver bridges will have ratings of 4 or below.

This means that $p = 0.09$

Use the forecast to find the probability that in a random sample of 12 major Denver bridges, at least 4 will have an inspection rating of 4 or below in 2020.

Either less than 4 have a rating of 4 or below, or at least 4 does. The sum of the probabilities of these events is 1.

So

$P(X < 4) + P(X \geq 4) = 1$

We want $P(X \geq 4)$

So

$P(X \geq 4) = 1 - P(X < 4)$

In which

$P(X < 4) = P(X = 0) + P(X = 1) + P(X = 2) + P(X = 3)$

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

$P(X = 0) = C_{12,0}.(0.09)^{0}.(0.91)^{12} = 0.3225$

$P(X = 1) = C_{12,1}.(0.09)^{1}.(0.91)^{11} = 0.3827$

$P(X = 2) = C_{12,2}.(0.09)^{2}.(0.91)^{10} = 0.2082$

$P(X = 3) = C_{12,3}.(0.09)^{3}.(0.91)^{9} = 0.0686$

$P(X < 4) = P(X = 0) + P(X = 1) + P(X = 2) + P(X = 3) = 0.3225 + 0.3827 + 0.2082 + 0.0686 = 0.982$

Finally

$P(X \geq 4) = 1 - P(X < 4) = 1 - 0.982 = 0.0180$

1.80% probability that in a random sample of 12 major Denver bridges, at least 4 will have an inspection rating of 4 or below in 2020.

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3 years ago

The adult height of a male is about 1.19 times his height at age 12. The adult height of a female is about 1.07 times her height

marissa [1.9K]

If you are 12 years old, just measure your own height, then multiply your height by 1.19 if you’re a male, or 1.07 if you’re a female.

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3 years ago

Read 2 more answers

What is 75% of 35 feet?

AleksandrR [38]

Answer:

26.25 feet

Step-by-step explanation:

A percentage is simply a ratio of the whole. If we assume 35 feet to be 100%, or the whole, then we can say the following:

0.75 * 35 == 26.25

Hence, 75% of 35 feet is 26.25 feet.

Cheers.

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3 years ago

Anyone know the answer please teach me

Semenov [28]

Answer: Look at step by step

Step-by-step explanation:

(a) There are 119 stocks that increased in price out of 246 stocks so the probability of selecting a stock that is increased in price is 119/246 = 48.37%

(b) There are 112 stocks where it pays dividends so the probability so the probability of selecting a stock that pays dividends is 112/246 = 45.53%

(c) There are 49 stocks which satisfy the question so the probability is 49/246 = 19.92%

(e) There are 34 stocks which increase in price and pay dividends out of the 119 stocks that increase in price so the probability is 34/119 = 28.57%

(f) Using the same logic as (e), the probability is 85/134 = 63.43%

(g) From the requirements, we see that 49 stocks don't satisfy the requirements, so the probability is (246-49)/246 = 80.08%

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1 year ago