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3 years ago

a country's population in 1992 waa 83 million and in 1996 was 88 million what was the population in 2013

1 answer:

4 0

The population in 1992 was 83 mill....population is 1996 was 88 mill...

so in 4 years (from 1992 to 1996), the population rose by (88 mill - 83 mill) = 5 mill

Thats 5,000,000 / 4 = 1,250,000 per year.

so in 2013 (17 years from 1996), the population would be :
83 mill + 1,250,000(17) = 83 mill + 2,125,000 = 85,125,000 <==

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To estimate the mean height μ of male students on your campus,you will measure an SRS of students. You know from government data

nexus9112 [7]

Answer:

a) $\sigma = 0.167$

b) We need a sample of at least 282 young men.

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

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

This Zscore is how many standard deviations the value of the measure X 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.

(a) What standard deviation must x have so that 99.7% of allsamples give an x within one-half inch of μ?

To solve this problem, we use the 68-95-99.7 rule. This rule states that:

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

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

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

In this problem, we want 99.7% of all samples give X within one-half inch of $\mu$ . So $X - \mu = 0.5$ must have $Z = 3$ and $X - \mu = -0.5$ must have $Z = -3$ .

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

$3 = \frac{0.5}{\sigma}$

$3\sigma = 0.5$

$\sigma = \frac{0.5}{3}$

$\sigma = 0.167$

(b) How large an SRS do you need to reduce the standard deviationof x to the value you found in part (a)?

You know from government data that heights of young men are approximately Normal with standard deviation about 2.8 inches. This means that $\sigma = 2.8$

The standard deviation of a sample of n young man is given by the following formula

$s = \frac{\sigma}{\sqrt{n}}$

We want to have $s = 0.167$

$0.167 = \frac{2.8}{\sqrt{n}}$

$0.167\sqrt{n} = 2.8$

$\sqrt{n} = \frac{2.8}{0.167}$

$\sqrt{n} = 16.77$

$\sqrt{n}^{2} = 16.77^{2}$

$n = 281.23$

We need a sample of at least 282 young men.

6 0

3 years ago

There are some red and blue balls in a bag of 21 balls and the probability of picking 2 red balls out in a row is 1/14 how many

Over [174]

Answer:

6 red balls

Step-by-step explanation:

The probability in the first pick

6/21

The probability in the second pick (without replacement)

5/20

the requested probability

(6/21)(5/20) = 30/420

simplification

30/420 = 3/42 = 1/14

Hope this helps

8 0

2 years ago

Read 2 more answers

"how many different rectangles" can you draw that have a perimeter of 12, 14

amm1812

Perimeter of rectangle = length + length + width + width

To find the combinations, think of two numbers that each multiplied by 2 and added up to give 12 or 14

Rectangle with perimeter 12

Say we take length = 2 and width = 3
Multiply the length by 2 = 2 × 2 = 4
Multiply the width by 3 = 2 × 3 = 6
Then add the answers = 4 + 6 = 10
This doesn't give us perimeter of 12 so we can't have the combination of length = 2 and width = 3

Take length = 4 and width = 2
Perimeter = 4+4+2+2 = 12
This is the first combination we can have

Take length = 5 and width = 1
Perimeter = 5+5+1+1 = 12
This is the second combination we can have

The question doesn't specify whether or not we are limited to use only integers, but if it is, we can only have two combinations of length and width that give perimeter of 12

length = 4 and width = 2
length = 5 and width = 1
--------------------------------------------------------------------------------------------------------------

Rectangle with perimeter of 14

Length = 4 and width = 3
Perimeter = 4+4+3+3 = 14

Length = 5 and width = 2
Perimeter = 5+5+2+2 = 14

Length = 6 and width = 1
Perimeter = 6+6+1+1 = 14

We can have 3 different combinations of length and width

3 0

3 years ago

Find WZ. PLEASE ONLY REAL ANSWERS!

Karo-lina-s [1.5K]

Step-by-step explanation:

look to the picture of my answer.