39,918.23 rounded to the nearest thousands is

The Census Bureau reports that 82% of Americans over the age of 25 are high school graduates. A survey of randomly selected resi

SVETLANKA909090 [29]

Answer:

a) Mean = 1030; Standard deviation = 12.38.

b) The county result is unusually high.

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

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

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. Subtracting 1 by the pvalue, we This p-value is the probability that the value of the measure is greater than X.

(a) Find the mean and standard deviation for the number of high school graduates in groups of 1210 Americans over the age of 25.

This first question is a binomial propability distribution.

We have a sample of 1210 Amricans, so $n = 1210$ .

The mean of the sample is 1030.

The probability of a success is $\pi = \frac{1030}{1210} = 0.8512$ .

The standard deviation of the sample is $s = \sqrt{n\pi(1-\pi)} = \sqrt{1210*0.8512*0.1488} = 12.38$

(b) Is that county result of 1030 unusually high, or low, or neither?

The first step is find the zscore when $X = 1030$ .

Then we find the pvalue of this zscore.

If this pvalue is bigger than 0.95, the county result is unusually high.

If this pvalue is smaller than 0.05, the county result is unusually low.

Otherwise, it is neither.

The national mean is 82%. So,

$\mu = 0.82(1210) = 992.2$

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

$Z = \frac{1030 - 992.2}{12.38}$

$Z = 3.05$

$Z = 3.05$ has a pvalue of 0.9989.This means that the county result is unusually high.

4 0

2 years ago

For a package to qualify for a certain postage rate, the sum of its length and girth cannot exceed 85 inches. If the girth is 63

tester [92]

Answer:

Length of package can be = 22 inches

Step-by-step explanation:

Given:

For a package to qualify for a certain postage rate, the sum of its length and girth cannot exceed 85 inches

To find length of package when girth of package is = 63 inches

Solution:

Let length of package be = $l$ inches

Let girth length of package be = $g$ inches

Sum of length and girth of package = $(l+g)$ inches

To qualify for a certain postage rate the sum of length and girth should not exceed 85 inches.

Thus, the inequality representing the situation can be given as:

$l+g\leq 85$

We are given girth of package is = 63 inches

So, inequality to find length would be:

$l+63\leq 85$

Subtracting both sides by 63.

$l+63-63\leq 85-63$

$l\leq 22$ inches

So, length should not exceed 22 inches in order to qualify.

Thus, the maximum length of package to qualify for the postal rate must be = 22 inches

3 0

1 year ago

What is the value of k in the equation below? 5k - 2k = 12? 1 1/5, 1 5/7, 3, 4

valkas [14]

Hi there!

5k - 2k = 12
Solve for K
3k = 12
Divide both sides by 3
3k/3 = 12/3
k = 4
The correct answer is : 4

I hope that helps!
Brainliest answer :)

8 0

1 year ago

Read 2 more answers

For each call, a certain phone company charges a connecting fee, and then a cost per minute after that. How much does each call'

Effectus [21]

The answer i got is B

4 0

1 year ago

A set of elementary school student heights are normally distributed with a mean of 105105105 centimeters and a standard deviatio

steposvetlana [31]

Answer:

The proportion of student heights that are between 94.5 and 115.5 is 86.64%

Step-by-step explanation:

We have a mean $\mu = 105$ and a standard deviation $\sigma = 7$ . For a value x we compute the z-score as $(x-\mu)/\sigma$ , so, for x = 94.5 the z-score is (94.5-105)/7 = -1.5, and for x = 115.5 the z-score is (115.5-105)/7 = 1.5. We are looking for P(-1.5 < z < 1.5) = P(z < 1.5) - P(z < -1.5) = 0.9332 - 0.0668 = 0.8664. Therefore, the proportion of student heights that are between 94.5 and 115.5 is 86.64%

4 0

2 years ago

Read 2 more answers