Simplify by using order of operation 20

The concentration of particles in a suspension is 50 per mL. A 5 mL volume of the suspension is withdrawn. a. What is the probab

kolezko [41]

Answer:

(a) 0.6579

(b) 0.2961

(c) 0.3108

(d) 240

Step-by-step explanation:

The random variable X can be defined as the number of particles in a suspension.

The concentration of particles in a suspension is 50 per ml.

Then in 5 mL volume of the suspension the number of particles will be,

5 × 50 = 250.

The random variable X thus follows a Poisson distribution with parameter, λ = 250.

The Poisson distribution with parameter λ, can be approximated by the Normal distribution, when λ is large say λ > 10.

The mean of the approximated distribution of X is:

μ = λ = 250

The standard deviation of the approximated distribution of X is:

σ = √λ = √250 = 15.8114

Thus, $X\sim N(250, 250)$

(a)

Compute the probability that the number of particles withdrawn will be between 235 and 265 as follows:

$P(235$

$=P(-0.95$

Thus, the value of P (235 < X < 265) = 0.6579.

(b)

Compute the probability that the average number of particles per mL in the withdrawn sample is between 48 and 52 as follows:

$P(48$

$=P(-0.28$

Thus, the value of $P(48$ .

(c)

A 10 mL sample is withdrawn.

Compute the probability that the average number of particles per mL in the withdrawn sample is between 48 and 52 as follows:

$P(48$

$=P(-0.40$

Thus, the value of $P(48$ .

(d)

Let the sample size be n.

$P(48$

$0.95=P(-z$

The value of z for this probability is,

z = 1.96

Compute the value of n as follows:

$z=\frac{\bar X-\mu}{\sigma/\sqrt{n}}\\\\1.96=\frac{48-50}{15.8114/\sqrt{n}}\\\\n=[\frac{1.96\times 15.8114}{48-50}]^{2}\\\\n=240.1004\\\\n\approx 241$

Thus, the sample selected must be of size 240.

5 0

3 years ago

Both students made a mistake.

Musya8 [376]

I’m so sorry! I hope you find the answer soon! I’m stressing out as well

5 0

2 years ago

an item is regularly priced at 60$ Carmen bought it at a discount of "70 %" off the regular price. How much did carmen play?

densk [106]

Your answer will be 10 dollars.

3 0

1 year ago

The scale from a square park to a drawing of the park is 5 miles to 1 miles. The actual park has an area of 1,600 m×2 what is th

Flauer [41]

The user corrected that the scale of a drawing of a park reads: 5 miles to 1 cm , and we know that the park measures 1,600 square meters (user insisted that this measure is given in square meters and not square miles).

So we have to convert the 1600 square meters into miles, knowing that 1 meter is the same as: 0.000621371 miles

then meters square will be equivalents to:

1 m^2 = (0.000621371 mi)^2

then 1600 m^2 = 0.00061776 mi^2

now, since 5 miles are represented by 1 cm, then 25 square miles will be represented by 1 square cm

and therefore 0.00061776 square miles will be the equivalent to:

0.00061776 / 25 cm^2 = 0.000024710 cm^2

So and incredibly small number of square cm.

I still believe that some of the information you gave me are not in meters but in miles. (For example, the park may not be in square meters but in squared miles). The park seems to have the size of a house according to the info.

3 0

1 year ago

The chairlift at a ski resort rises a total of 2600 feet from where it starts. The angle of elevation is about 22.3 degrees. How

Monica [59]

Answer:

6852 feet .

Step-by-step explanation:

Refer the attached figure

The chairlift at a ski resort rises a total of 2600 feet from where it starts. i.e.AB = 2600 feet

The angle of elevation is about 22.3 degrees.i.e.∠ACB= 22.3°

We are supposed to find How far do riders travel on the lift i.e.AC

In ΔABC