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3 years ago

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A bag contains 2 gold marbles, 10 silver marbles, and 26 black marbles. You randomly select one marble from the bag. What is the

probability that you select a gold marble? Give your answer as a reduced fraction.

1 answer:

olga nikolaevna [1]3 years ago

4 0

Answer:

1/1 9

Step-by-step explanation:

ok

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Required information An article presents a new method for timing traffic signals in heavily traveled intersections. The effectiv

Natasha2012 [34]

Answer:

$652.6-2.01\frac{311.7}{\sqrt{50}}=563.997$

$652.6+2.01\frac{311.7}{\sqrt{50}}=741.203$

So on this case the 95% confidence interval would be given by (563.997;741.203)

Step-by-step explanation:

Previous concepts

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".

$\bar X=652.6$ represent the sample mean for the sample

$\mu$ population mean (variable of interest)

s=311.7 represent the sample standard deviation

n=50 represent the sample size

Soltuion to the problem

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

$\bar X \pm t_{\alpha/2}\frac{s}{\sqrt{n}}$ (1)

In order to calculate the critical value $t_{\alpha/2}$ we need to find first the degrees of freedom, given by:

$df=n-1=50-1=49$

Since the Confidence is 0.95 or 95%, the value of $\alpha=0.05$ and $\alpha/2 =0.025$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-T.INV(0.025,49)".And we see that $t_{\alpha/2}=2.01$

Now we have everything in order to replace into formula (1):

$652.6-2.01\frac{311.7}{\sqrt{50}}=563.997$

$652.6+2.01\frac{311.7}{\sqrt{50}}=741.203$

So on this case the 95% confidence interval would be given by (563.997;741.203)

6 0

3 years ago

PLEASE HELP!!!!!! URGENT!!

Stolb23 [73]

Answer: the answer is 76 please give me brainliest im trying to rank up.

6 0

3 years ago

1+Sin/Cos + Cos/1+Sin = 2Sec

Bond [772]

Step-by-step explanation:

Consider the left-hand side:

$\dfrac{1+\sin{\theta}}{\cos{\theta}} + \dfrac{\cos{\theta}}{1+\sin{\theta}}$

$\:\:\:\:= \dfrac{(1+\sin{\theta})^2 + \cos^2{\theta}}{\cos{\theta}(1+\sin{\theta})}$

$\:\:\:\:=\dfrac{1+2\sin{\theta}+\sin^2{\theta} + \cos^2{\theta}}{\cos{\theta}(1+\sin{\theta})}$

$\:\:\:\:=\dfrac{2+2\sin{\theta}}{\cos{\theta}(1+\sin{\theta})} =\dfrac{2(1+\sin{\theta})}{\cos{\theta}(1+\sin{\theta})}$

$\:\:\:\:= \dfrac{2}{\cos{\theta}} = 2\sec{\theta}$

7 0

2 years ago

dalvyx [7]

Using the Poisson distribution, it is found that there is a 0.507 = 50.7% probability that the bird feeder will be visited by at most 5 birds in a 45 minute period during daylight hours.

<h3>What is the Poisson distribution?</h3>

In a Poisson distribution, the probability that X represents the number of successes of a random variable is given by:

$P(X = x) = \frac{e^{-\mu}\mu^{x}}{(x)!}$

The parameters are:

x is the number of successes

e = 2.71828 is the Euler number

$\mu$ is the mean in the given interval.

Considering the average of 15 birds every 2 hours during daylight hours, the mean for a 45-minute period is given by:

$\mu = 15 \times \frac{45}{120} = 5.625$

The probability that the bird feeder will be visited by at most 5 birds in a 45 minute period during daylight hours is given by:

$P(X \leq 5) = P(X = 0) + P(X = 1) + P(X = 2) + P(X = 3) + P(X = 4) + P(X = 5)$

In which:

$P(X = x) = \frac{e^{-\mu}\mu^{x}}{(x)!}$

$P(X = 0) = \frac{e^{-5.625}(5.625)^{0}}{(0)!} = 0.004$

$P(X = 1) = \frac{e^{-5.625}(5.625)^{1}}{(1)!} = 0.02$

$P(X = 2) = \frac{e^{-5.625}(5.625)^{2}}{(2)!} = 0.057$

$P(X = 3) = \frac{e^{-5.625}(5.625)^{3}}{(3)!} = 0.107$

$P(X = 4) = \frac{e^{-5.625}(5.625)^{4}}{(4)!} = 0.150$

$P(X = 5) = \frac{e^{-5.625}(5.625)^{5}}{(5)!} = 0.169$

Then:

$P(X \leq 5) = P(X = 0) + P(X = 1) + P(X = 2) + P(X = 3) + P(X = 4) + P(X = 5) = 0.004 + 0.02 + 0.057 + 0.107 + 0.15 + 0.169 = 0.507$

0.507 = 50.7% probability that the bird feeder will be visited by at most 5 birds in a 45 minute period during daylight hours.

More can be learned about the Poisson distribution at brainly.com/question/13971530

#SPJ1

3 0

1 year ago

T + 23.7 = 80.66 .............?

grin007 [14]

Answer: 56.96

Step-by-step explanation: 80.66 - 23.7 = 56.96

HOPE THIS HELP :D

4 0

3 years ago

Read 2 more answers