Solve the inequality 38<4x+3+7-3x

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

Plz..Help Me Solve This ...

puteri [66]

R = recycling and reuse industry jobs
w = waste management jobs

we know, those two jobs combined are 1,275,000
or
r + w = 1,275,000

we also know that, whatever the "w" jobs are, are really less than "r"
jobs by 1,025,000

"r" has 1,025,000 more than "w"
or
r = w + 1,025,000
or
r-w = 1,025,000

so... there, just solve by elimination, simple, notice the "w",
is just waiting to be eliminated :)

$\bf \begin{cases}
r+\quad w=1,275,000\\
r-\quad w=1,025,000\\
\textendash\textendash\textendash\textendash\textendash\textendash\textendash\textendash\textendash\textendash\textendash\textendash\textendash\textendash\textendash\textendash\\
\boxed{?}+\boxed{?}=\boxed{?}
\end{cases}$

7 0

3 years ago

about 7.5 gallons of water will fill up 1 cubic foot of space. how many gallons of water will fill a goldfish pool shaped like t

Cloud [144]

Well, since there is no image I am unable to say the exact volume. But here is the volume formula-
V=L times W times H
*V=volume W=width H=height
and you don't actually have to write times you can do the symbol.

Example- if I had a rectangular prism of the width being 5 cubes, the length 8 cubes, and the height 7 cubes(following how many gallons are in a cube 7.5) I would the use my formula. V=LWH- 8 times 7= 56 56 times 5=280 280 times 7.5= 2100
V=2100 (that is your answer reply If you didn't mean the volume or you don't get it)

7 0

3 years ago

Read 2 more answers

Broccoli cost $1.50 per pound at the store.How much money does 32 ounces of broccoli cost

balandron [24]

Hope this will help u

8 0

3 years ago

Your crew can pave two driveways in a day. You work five days per week but take off 2 weeks each year for holidays and vacations

k0ka [10]

According to Philippine Payroll Regulations and Information, there will be a total of 247 working days for all employees working from Mondays to Fridays and considered Saturdays and Sundays as rest days. If the two weeks off is referring to employees working days only, it means employee can file a leave for 14 equivalent days off. Computations will be Total driveways= (247 days-14 days off) * 2 driveways per day and the answer is 466 driveways.

5 0

3 years ago