1/4 = x/12 solve for x

Life Expectancies In a study of the life expectancy of people in a certain geographic region, the mean age at death was years an

Sphinxa [80]

Answer:

The probability that the mean life expectancy of the sample is less than X years is the p-value of $Z = \frac{X - \mu}{\frac{\sigma}{\sqrt{n}}}$ , in which $\mu$ is the mean life expectancy, $\sigma$ is the standard deviation and n is the size of the sample.

Step-by-step explanation:

To solve this question, we need to understand the normal probability distribution and the central limit theorem.

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.

Central Limit Theorem

The Central Limit Theorem establishes that, for a normally distributed random variable X, with mean $\mu$ and standard deviation $\sigma$ , the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean $\mu$ and standard deviation $s = \frac{\sigma}{\sqrt{n}}$ .

For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.

We have:

Mean $\mu$ , standard deviation $\sigma$ .

Sample of size n:

This means that the z-score is now, by the Central Limit Theorem:

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

Find the probability that the mean life expectancy will be less than years.

The probability that the mean life expectancy of the sample is less than X years is the p-value of $Z = \frac{X - \mu}{\frac{\sigma}{\sqrt{n}}}$ , in which $\mu$ is the mean life expectancy, $\sigma$ is the standard deviation and n is the size of the sample.

8 0

2 years ago

Question in screen shot

alisha [4.7K]

The two graphs in D are not inverses of each other.

6 0

2 years ago

Hannah claims that people who live in southern states spend 9 hours more per week outside than do people in northern states. She

Aneli [31]

Answer: Hello your question is incomplete below is the missing part

Which of the following statements about Hannah’s claim is supported by the interval?

A) Hannah is likely to be incorrect because the difference in the sample means was 18.6−14.4=4.218.6−14.4=4.2 hours.

B) Hannah is likely to be incorrect because 9 is not contained in the interval.

C)The probability that Hannah is correct is 0.99 because 9 is not contained in the interval.

D)The probability that Hannah is correct is 0.01 because 9 is not contained in the interval.

E)Hannah is likely to be correct because the difference in the sample means (18.6−14.4=4.2)(18.6−14.4=4.2) is contained in the interval.

Answer : Hannah is likely to be incorrect because 9 is not contained in the interval. ( B )

Step-by-step explanation:

The statement that is supported by the interval in Hannah's claim is that

Hannah is likely to be incorrect because 9 is not contained in the interval.

5 0

3 years ago

[1x-6]>1 what are the solutions

a_sh-v [17]

Answer:

x > 7

(I think this is Right but not sure yet )

3 0

3 years ago

Find the 3rd term in the expansion of (a+b)^8 in simplest form.

Art [367]

Answer:

The fifth term is the middle term of nine, with coefficient given by all the ways of choosing 4 items out of 8 , namely the ways of choosing 4 a 's out of 8 binomial factors.

Step-by-step explanation:

4 0

3 years ago