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3 years ago

15

Factorize (x+3)+5(x+3)

1 answer:

Free_Kalibri [48]3 years ago

8 0

6x + 18, that is the answer

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Assume that the empirical rule is a good model for the time it takes for all passengers to board an airplane. The mean time is 4

slamgirl [31]

Answer:

The interval that describes how long it takes for passengers to board the middle 95% of the time is between 40.16 minutes and 55.84 minutes.

Step-by-step explanation:

Problems of normally distributed samples can be solved using the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the zscore 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 pvalue, we get the probability that the value of the measure is greater than X.

In this problem, we have that:

$\mu = 48, \sigma = 4$ .

Which interval describes how long it takes for passengers to board the middle 95% of the time?

This is between the 2.5th percentile and the 97.5th percentile.

So this interval is the value of X when Z has a a pvalue of 0.025 and the value of X when Z has a pvalue of 0.975

Lower Limit

Z has a pvalue of 0.025 when $Z = -1.96$ . So

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

$-1.96 = \frac{X - 48}{4}$

$X - 48 = -1.96*4$

$X = 40.16$

Upper Limit

Z has a pvalue of 0.975 when $Z = 1.96$ . So

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

$1.96 = \frac{X - 48}{4}$

$X - 48 = 1.96*4$

$X = 55.84$

The interval that describes how long it takes for passengers to board the middle 95% of the time is between 40.16 minutes and 55.84 minutes.

7 0

3 years ago

There are 100 sophomores at the school. 85% of them are good students. What would be the percent of good students at school if (

klemol [59]

Answer:

77%

Step-by-step explanation:

7 0

3 years ago

Gary wrote the comparison below.

scoray [572]

Answer:

what box?

Step-by-step explanation:

5 0

3 years ago

Read 2 more answers

Find the standard deviation of the following data. Round your answer to one decimal place. x 0 1 2 3 4 5 P(X

lbvjy [14]

Answer:

<em></em> $\sigma = 1.8$ <em></em>

<em></em>

Step-by-step explanation:

Given

$\begin{array}{ccccccc}x & {0} & {1} & {2} & {3} & {4}& {5} \ \\ P(x) & {0.2} & {0.1} & {0.1} & {0.2} & {0.2}& {0.2} \ \end{array}$

Required

The standard deviation

First, calculate the expected value E(x)

$E(x) = \sum x * P(x)$

So, we have:

$E(x) = 0 * 0.2 + 1 * 0.1 + 2 * 0.1 + 3 * 0.2 + 4 * 0.2 + 5 * 0.2$

$E(x) = 2.7$

Next, calculate E(x^2)

$E(x^2) = \sum x^2 * P(x)$

So, we have:

$E(x^2) = 0^2 * 0.2 + 1^2 * 0.1 + 2^2 * 0.1 + 3^2 * 0.2 + 4^2 * 0.2 + 5^2 * 0.2$

$E(x^2) = 10.5$

The standard deviation is:

$\sigma = \sqrt{E(x^2) - (E(x))^2}$

$\sigma = \sqrt{10.5 - 2.7^2}$

$\sigma = \sqrt{10.5 - 7.29}$

$\sigma = \sqrt{3.21}$

<em></em> $\sigma = 1.8$ <em> --- approximated</em>

5 0

3 years ago

The probability that John will drive to school is 0.31, the probability that he will ride with friends is 0.12, and the probabil

garri49 [273]

Answer:

P(company) = P(ride with friends) + P(with parents) = .23 + .4 = .63 0r 63%

Step-by-step explanation:

The 3 different case scenarios are independent of one another:.37 + .23 + .4 = 1

P of two of them occurring is found by adding their individual Probabilities

8 0

3 years ago