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Aleonysh [2.5K]

2 years ago

10

A scientist measures the height of 30 pine trees. When he finds the mean of these data, which phase of inferential statistics wi

ll it represent?

2 answers:

Andreyy892 years ago

8 0

Its data analysis, apex

grigory [225]2 years ago

7 0

Answer:

Data analysis

Step-by-step explanation:

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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

2 years ago

A countertop is 16 feet long and 3 feet wide. what is the area of the countertop in square meters

Paladinen [302]

The area of the countertop is (16-ft x 3-ft) = 48 feet² .

1 foot = 0.3048 meter (rounded)

(1 foot)² = (0.3048 meter)² = 0.0929 meter²

48 feet² = (48 x 0.0929) = 4.459 meter² (rounded)

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3 years ago

Susie has $2 in coins in her purse. She has 3 times as many quarters as nickels. She has twice as many dimes as nickels. How man

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Answer:

120 coins our in her purse if the 2 dollar factor is made up of nickels

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3 years ago

What is the sum of the interior<br> angles of a polygon that has 7<br> sides?

IgorC [24]

Answer:

900

Step-by-step explanation:

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3 years ago

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Certain gases in the atmosphere trap heat on Earth.

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<span>C.
glacial melting<<<<<<<<<<<<<<<</span>

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3 years ago