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3 years ago

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Mathematics

1 answer:

Akimi4 [234]3 years ago

7 0

Answer:

1.d

2.c

3.b

4.a

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

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2 years ago

Im just giving out points whats 2+1

omeli [17]

Answer:

Step-by-step explanation:

3 mah fwend omg so hard my brain hurts

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3 years ago

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you roll a six sided number cube and flip a coin what is the probability of rolling a number greater than 5 and flipping heads?

Whitepunk [10]

Answer:

0.08333... or 8.333...%

Step-by-step explanation:

1/6 * 1/2 = 1/12

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2 years ago

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Pleases complete the proof but with each step can you tell me which property of equality to use.

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1 year ago

Tom's hair was originally 4 inches long. He asked her hairdresser to cut 1 ⁄3of it off. How many inches did he have cut off?

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Answer:

About 3.67

Step-by-step explanation:

1 - 1/3 = 3.66666666667

And 3.66666666667 ≈ 3.67

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3 years ago