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Crazy boy [7]
3 years ago
9

A clothing store has a section of jeans on sale. There is a 30% chance of picking a pair with a 30-inch inseam; a 25% chance of

picking a pair with a 32-inch inseam; a 10% chance of picking a pair with a 34-inch inseam; a 10% chance of picking a pair with a 36-inch inseam; a 10% chance of picking a pair with a 38-inch inseam; and a 15% chance of picking a pair with a 40-inch inseam. Find the expected value of the inseam length of the jeans.
33

33.4

33.8

35
Mathematics
1 answer:
Andrej [43]3 years ago
3 0

The expected value of the inseam length of the jeans is found as

30% of 30+ 25% of 32+ 10% of 34+ 10% of 36 + 10% of 38 + 15% of 40

= \frac{30}{100}\times30 +\frac{25}{100}\times32+ \frac{10}{100}\times34+ \frac{10}{100}\times36 +\frac{10}{100}\times38+ \frac{15}{100}\times40

= 9+8+3.4+3.6+3.8+6=33.8

Hence, the third option 33.8 is the correct expected value.

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en un maratòn participan corredores de todos los continentes 5/6 de los corredores son europeos se sabe que los americanos son l
Marysya12 [62]

Usando proporciones, se encuentra que 400 africanos han participado.

En total, hay x participantes.

\frac{5}{6} de los corredores son europeos, o sea:

E = \frac{5x}{6}

Los americanos son la dècime parte de los europeos, o sea:

Am = \frac{1}{10}E = \frac{5x}{60} = \frac{x}{12}

Los africanos son la quinta parte de los americanos, o sea:

Afr = \frac{1}{5}Am = \frac{x}{60}

En la carrera han inscritos 24 000 participantes, o sea, x = 24000. Por eso, la cantidad de africanos es:

Afr = \frac{x}{60} = \frac{24000}{60} = 400

Para obtener más información sobre las proporciones, puedes visitar a brainly.com/question/24615636

8 0
2 years ago
The heights of a random sample of 50 college students showed a mean of 174.5 centimeters and a standard deviation of 6.9 centime
Minchanka [31]

Answer:

Step-by-step explanation:

Hello!

For me, the first step to any statistics exercise is to determine what is the variable of interest and it's distribution.

In this example the variable is:

X: height of a college student. (cm)

There is no information about the variable distribution. To estimate the population mean you need a variable with at least a normal distribution since the mean is a parameter of it.

The option you have is to apply the Central Limit Theorem.

The central limit theorem states that if you have a population with probability function f(X;μ,δ²) from which a random sample of size n is selected. Then the distribution of the sample mean tends to the normal distribution with mean μ and variance δ²/n when the sample size tends to infinity.

As a rule, a sample of size greater than or equal to 30 is considered sufficient to apply the theorem and use the approximation.

The sample size in this exercise is n=50 so we can apply the theorem and approximate the distribution of the sample mean to normal:

X[bar]~~N(μ;σ2/n)

Thanks to this approximation you can use an approximation of the standard normal to calculate the confidence interval:

98% CI

1 - α: 0.98

⇒α: 0.02

α/2: 0.01

Z_{1-\alpha /2}= Z_{1-0.01}= Z_{0.99} =2.334

X[bar] ± Z_{1-\alpha /2} * \frac{S}{\sqrt{n} }

174.5 ± 2.334* \frac{6.9}{\sqrt{50} }

[172.22; 176.78]

With a confidence level of 98%, you'd expect that the true average height of college students will be contained in the interval [172.22; 176.78].

I hope it helps!

4 0
2 years ago
Ticketd to the school play cost $11 for adults and $6 for children. What expression can be used to find the toyal cost for x adu
Makovka662 [10]

Answer:221

Step-by-step explanation:

4 0
3 years ago
What is the box-and-whiskers plot used to show?
12345 [234]
The whole idea of that kind of graph is that they allow you to view the complete distribution of data while also being able to see first and third quartiles, the median, and the minimums and maximums. 
5 0
2 years ago
a photographer is taking the 4th grade class picture. She stands on a ladder to get a better angle . From the top step of the la
Kruka [31]
Given:
a ladder with three steps.
top step is 45° angle.

45° / 3 steps = 15°

So, top step is 45°. Middle step is 30°. Bottom step is 15°. Ground is 0°

The photographer would shout on the bottom step at an angle of 15°.
4 0
3 years ago
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