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3 years ago

Two nonadjacent angles formed by two intersecting lines are

Mathematics

1 answer:

Sophie [7]3 years ago

6 0

Two vertical angles are formed. These angles are also equal to each other.

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Calculate the sample mean and sample variance for the following frequency distribution of heart rates for a sample of American a

spin [16.1K]

Answer:

$Mean = 68.9$

$s^2 =18.1$ --- Variance

Step-by-step explanation:

Given

$\begin{array}{cccccc}{Class} & {51-58} & {59-66} & {67-74} & {75-82} & {83-90} \ \\ {Frequency} & {6} & {3} & {11} & {13} & {4} \ \end{array}$

Solving (a): Calculate the mean.

The given data is a grouped data. So, first we calculate the class midpoint (x)

For 51 - 58.

$x = \frac{1}{2}(51+58) = \frac{1}{2}(109) = 54.5$

For 59 - 66

$x = \frac{1}{2}(59+66) = \frac{1}{2}(125) = 62.5$

For 67 - 74

$x = \frac{1}{2}(67+74) = \frac{1}{2}(141) = 70.5$

For 75 - 82

$x = \frac{1}{2}(75+82) = \frac{1}{2}(157) = 78.5$

For 83 - 90

$x = \frac{1}{2}(83+90) = \frac{1}{2}(173) = 86.5$

So, the table becomes:

$\begin{array}{cccccc}{x} & {54.5} & {62.5} & {70.5} & {78.5} & {86.5} \ \\ {Frequency} & {6} & {3} & {11} & {13} & {4} \ \end{array}$

The mean is then calculated as:

$Mean = \frac{\sum fx}{\sum f}$

$Mean = \frac{54.5*4+62.5*3+70.5*11+78.5*13+86.5*4}{6+3+11+13+4}$

$Mean = \frac{2547.5}{37}$

$Mean = 68.9$ -- approximated

Solving (b): The sample variance:

This is calculated as:

$s^2 =\frac{\sum (x - \overline x)^2}{\sum f - 1}$

So, we have:

$s^2 =\frac{(54.5-68.9)^2+(62.5-68.9)^2+(70.5-68.9)^2+(78.5-68.9)^2+(86.5-68.9)^2}{37 - 1}$

$s^2 =\frac{652.8}{36}$

$s^2 =18.1$ -- approximated

5 0

3 years ago

What is 11 minus a number to equal -3

NNADVOKAT [17]

Answer:

Step-by-step explanation:

11 - n = -3

-n = -3 - 11 = -14

n = 14

add n to both sides of equation and add 3 to both sides of equation:

11 - n + n + 3 = -3 + n + 3 ----> n = 14

3 0

3 years ago

Answer? 225 or 300?

saveliy_v [14]

-7(x+y=525)-7
3x+7y=2775

-7x-7y=-3675
3x+7y=2775

-4x=-900
X=-900/-4
X=225
Answer is c

6 0

3 years ago

I need help please. The question is already there. Tysm. 20 points.

Bess [88]

Answer:

$109 and 35%

Step-by-step explanation:

49.05 is the sale price and the discount is 55%. What’s the original price?

price/ 1- discount

49.05/ 1 - 0.55

49.05/ 0.45

109

for the other part

to find the discount subtract final price from original price

94 - 61.10 = 32.9

Which would be 35% in percent form.

5 0

3 years ago

The population p (in millions) of Italy from 1990 through 2008 can be approximated by the model p=56.8e^o.oo15t , where t repres

dimulka [17.4K]

As we already have the model that describes the change of the population in Italy in terms of the years that have elapsed, we only have to replace the conditions that are requested in that equation.

Therefore to find the population of Italy in the year 2000 (t = 10 years) substitute t = 10 in the equation and have:

$p = 56.8e^{0.0015*10}\\$

$p=57.6584$ million people

To find the population of Italy in 2008 (t = 18 years)

substitute t = 18 in the equation and have:

$p=56.8e ^{0.0015*18}\\$

$p=58.3545$ million people

To predict the population in Italy for 2015 and 2020 with this model, we substitute in the equation t = 25 and t = 30

t = 25

$p=56.8e^{0.0015*25}$

$p=58.9704$ million people

t = 30

$p=56.8e^{0.0015*30}$

$p=59.4144$ million people

8 0

3 years ago