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3 years ago

Please please please help me with this question and show your work.

Mathematics

1 answer:

lawyer [7]3 years ago

4 0

The correct answer is D. You can see It is the biggest bar and so you can estimate the correct answer.

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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

The police in a certain city are investigating whether the proportion of minor traffic accidents is greater on Friday nights tha

Ganezh [65]

What city lol? sorry i just need to answer so i can ask question bc i’m lost lol

8 0

2 years ago

Completely factor the expression 16t^3 - 50t^2 + 36t

NikAS [45]

$\bf 16t^3-50t^2+36t\implies 2t[8t^2-25t+18]\implies 2t[(8t-9)(t-2)]$

4 0

3 years ago

The polynomial below is perfect square trinomial of the form a^2 -2AB +B^2

guajiro [1.7K]

Answer:

In order to get this perfect square trinomial, the factored form will be (a - b)^2

Step-by-step explanation:

We know this because it follows the rule of perfect squares in which the ends are both squares and the middle term is -2 times each term.

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3 years ago

For what values of x:

Anna71 [15]

Answer:

x=5 and x=6

Step-by-step explanation:

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3 years ago