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2 years ago

Math problem ⚠️ ⚠️⚠️⚠️⚠️⚠️⚠️⚠️⚠️

Mathematics

1 answer:

kvasek [131]2 years ago

3 0

Answer:

can you take a clearer photo of the problem?

Step-by-step explanation:

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A toy baseball and bat cost $1.50 together. The bat costs $1.00 more than the baseball. How much does the baseball cost?

Nataly [62]

$0.50 is the answer. If the bat is $1.00 more than the baseball, you would subtract that from the total cost which is $1.50 so the answer would be $0.50.

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3 years ago

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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

Mrs Ross class has 24 students. 2/3 of her students have brown hair. The rest have blonde hair. How many students have brown hai

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16 brown hair students Eight blonde hair students

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3 years ago

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A bag contains an unknown number of marbles. You know that P(red) = 1 and P(green) = 1. What can you conclude about how many mar

Nataly [62]

The number of marbles in the bag illustrates probability

The conclusion about the number of marbles in the bag is that the bag can only contain one type of marble

<h3>The number of marbles in the bag?</h3>

The probabilities are given as:

P(Red) = 1

P(Green) = 1

For a distribution, the sum of all probabilities must equal to 1.

This means that:

P(Red) + P(Green) = 1

So, we have:

1 + 1 = 1

This gives

2 = 1

The above equation is false because 2 does not equal to 1.

So, the conclusion about the number of marbles in the bag is that the bag can only contain one type of marble i.e. either red marbles are in the bag or blue marbles are in the bag