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zlopas [31]
3 years ago
15

Determine the two z-scores that separate the middle 87.4% of the distribution from the area in the tails of the standard normal

distribution.​

Mathematics
1 answer:
marusya05 [52]3 years ago
4 0

The two z-scores are -1.53 and 1.53

Step-by-step explanation:

To find the two z-scores that separate the middle 87.4% of the distribution from the area in the tails of the standard normal distribution

  1. Assume that z-score is between -c and c ⇒ P(-c < z < c) = the given value
  2. Find the value of P(z < -c or z > c) = 1 - the given value
  3. P(z < -c) + P(z > c) = the answer of the previous step
  4. 2*P(z < -c) = the answer of the previous step
  5. Find the value of P(z < -c)
  6. In the z-table having area to the left of z, look for the value closest to the value of P(z < -c) inside the table to find the closest value of z

∵ P(-c < z < c) = 87.4%

∵ 87.4% = 87.4 ÷ 100 = 0.874

∴ P(-c < z < c) = 0.874

∵ P(z > c) = 1 - 0.874 = 0.126

∴ P(z < -c) + P(z > c) = 0.126

∵ P(z > c) = P(z < -c)

∴ P(z < -c) + P(z < -c) = 0.126

∴ 2*P(z < -c) = 0.126

- Divide both sides by 2

∴ P(z < -c) = 0.063

Let us use the z-table to find the corresponding values of

z to 0.063

∵ The corresponding value of z to 0.063 = -1.53

∴ The two z-scores = -1.53 and 1.53

The attached figure for more understand

The two z-scores are -1.53 and 1.53

Learn more:

You can learn more about z-score in brainly.com/question/6270221

#LearnwithBrainly

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Answer:

The travel time that separates the top 2.5% of the travel times from the rest is of 91.76 seconds.

Step-by-step explanation:

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 of 80 seconds and a standard deviation of 6 seconds.

This means that \mu = 80, \sigma = 6

What travel time separates the top 2.5% of the travel times from the rest?

This is the 100 - 2.5 = 97.5th percentile, which is X when Z has a p-value of 0.975, so X when Z = 1.96.

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

1.96 = \frac{X - 80}{6}

X - 80 = 6*1.96

X = 91.76

The travel time that separates the top 2.5% of the travel times from the rest is of 91.76 seconds.

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Suppose N has a geometric distribution with parameter p. Derive a closed-form expression for E(N | N &lt;= k), k = 1,2,... Check
vfiekz [6]

Answer:

P(X= k) = (1-p)^k-1.p

Step-by-step explanation:

Given that the number of trials is

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Given p = success,

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Pr((X=k) = (1 - p)^ (k-1) .p

Since N<=k

Pr (X =k) = p(1-p)^k-1, k= 1,2,...k

0, elsewhere

If the probability is defined for Y, the number of failure before a success

Pr (Y= k) = p(1-p)^y......k= 0,1,2,3

0, elsewhere.

Given p= 0.2, k= 3,

P(X= 3) =( 0.2) × (1 - 0.2)²

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Step-by-step explanation:

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Step-by-step explanation:

We are given the system of equations:

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We need to solve the systems to find the values of x and y.

Let:

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So, value of x=6

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The number of bat  tomato sauce that can be made = y = 3 batches

Keywords: System of equations

Learn more about system of equations at:

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