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Afina-wow [57]
3 years ago
7

[6+4=10 points] Problem 2. Suppose that there are k people in a party with the following PMF: • k = 5 with probability 1 4 • k =

10 with probability 1 4 • k = 15 with probability 1 2 1) What is the probability that at least two people were born in the same month? Assume that all months are equally likely. Make sure to provide all decimal places in the answer. 2) Given that there are at least two people that celebrate their birthdays in the same month, what is the probability that k = 10?. Make sure to provide all decimal places in the answer.
Mathematics
1 answer:
kirza4 [7]3 years ago
6 0

Answer:

1). 0.903547

2). 0.275617

Step-by-step explanation:

It is given :

K people in a party with the following :

i). k = 5 with the probability of $\frac{1}{4}$

ii). k = 10 with the probability of $\frac{1}{4}$

iii). k = 10 with the probability $\frac{1}{2}$

So the probability of at least two person out of the 'n' born people in same month is  = 1 - P (none of the n born in the same month)

= 1 - P (choosing the n different months out of 365 days) = 1-\frac{_{n}^{12}\textrm{P}}{12^2}

1). Hence P(at least 2 born in the same month)=P(k=5 and at least 2 born in the same month)+P(k=10 and at least 2 born in the same month)+P(k=15 and at least 2 born in the same month)

= \frac{1}{4}\times (1-\frac{_{5}^{12}\textrm{P}}{12^5})+\frac{1}{4}\times (1-\frac{_{10}^{12}\textrm{P}}{12^{10}})+\frac{1}{2}\times (1-\frac{_{15}^{12}\textrm{P}}{12^{15}})

= 0.25 \times 0.618056 + 0.25 \times 0.996132 + 0.5 \times 1

= 0.903547

2).P( k = 10|at least 2 share their birthday in same month)

=P(k=10 and at least 2 born in the same month)/P(at least 2 share their birthday in same month)

= $0.25 \times \frac{0.996132}{0.903547}$

= 0.0.275617

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The resting heart rate for an adult horse should average about µ = 47 beats per minute with a (95% of data) range from 19 to 75
KatRina [158]

Answer:

a. 0.0582 = 5.82% probability that the heart rate is less than 25 beats per minute.

b. 0.1762 = 17.62% probability that the heart rate is greater than 60 beats per minute.

c. 0.7656 = 76.56% probability that the heart rate is between 25 and 60 beats per minute

Step-by-step explanation:

Empirical Rule:

The Empirical Rule states that, for a normally distributed random variable:

Approximately 68% of the measures are within 1 standard deviation of the mean.

Approximately 95% of the measures are within 2 standard deviations of the mean.

Approximately 99.7% of the measures are within 3 standard deviations of the mean.

Normal Probability Distribution:

Problems of normal distributions can be solved using the z-score formula.

In a set with mean \mu and standard deviation \sigma, the z-score of a measure X is given by:

Z = \frac{X - \mu}{\sigma}

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.

Mean:

\mu = 47

(95% of data) range from 19 to 75 beats per minute.

This means that between 19 and 75, by the Empirical Rule, there are 4 standard deviations. So

4\sigma = 75 - 19

4\sigma = 56

\sigma = \frac{56}{4} = 14

a. What is the probability that the heart rate is less than 25 beats per minute?

This is the p-value of Z when X = 25. So

Z = \frac{X - \mu}{\sigma}

Z = \frac{25 - 47}{14}

Z = -1.57

Z = -1.57 has a p-value of 0.0582.

0.0582 = 5.82% probability that the heart rate is less than 25 beats per minute.

b. What is the probability that the heart rate is greater than 60 beats per minute?

This is 1 subtracted by the p-value of Z when X = 60. So

Z = \frac{X - \mu}{\sigma}

Z = \frac{60 - 47}{14}

Z = 0.93

Z = 0.93 has a p-value of 0.8238.

1 - 0.8238 = 0.1762

0.1762 = 17.62% probability that the heart rate is greater than 60 beats per minute.

c. What is the probability that the heart rate is between 25 and 60 beats per minute?

This is the p-value of Z when X = 60 subtracted by the p-value of Z when X = 25. From the previous two items, we have these two p-values. So

0.8238 - 0.0582 = 0.7656

0.7656 = 76.56% probability that the heart rate is between 25 and 60 beats per minute

3 0
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What quantity of a 50% acid solution must be mixed with a 20% solution to produce 600 mL of a 45% solution?
Naddika [18.5K]

Answer:

400 mL

Step-by-step explanation:

0.50x + 0.20(600-x) = 0.40*600

50x + 20*600 - 20x = 40*600

30x = 20*600

x = 20*20

x = 400 mL

4 0
3 years ago
Solve 0.25[2.5x + 1.5(x – 4)] = –x.
zheka24 [161]

Answer:

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Step-by-step explanation:

0.25[2.5x + 1.5(X-4)]= -X

0.25[2.5x + 1.5x - 6] = -x

0.25[4x -6] = -x

1x + x = 1.5

2x = 1.5

x = 1.5/2

x = 0.75

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Which expression is equivalent to 42 + 30?
Zanzabum
42+30= 72
6 (36+24)=120 not equal
7 (6+30)=252 not equal
6 (7+5)=72 equal
5 (37+35)= 360 not equal
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What expression can be used for estimating 868 divided by 28
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868 is about 870, and 28 is about 30, so your expression would be 870 divided by 30 which would be 29 and the actual answer is 31, so your estimate would be close to your actual answer.
6 0
3 years ago
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