Help me please and thank you

A group of physical education majors was discussing the heights of female runners and whether female runners tended to be tall,

Anna11 [10]

Answer:

The 90% confidence interval for the mean µ of the population of female runners.

( 65.0328 , 66.5672)

Step-by-step explanation:

Step(i)

Given A sample of 12 runners showed a sample mean height of 65.80 inches and a sample standard deviation of 1.95 inches.

Given sample size is n = 12 <30 so small sample

Given sample mean (x⁻) = 65.80 inches

sample standard deviation (S) = 1.95 inches.

Step(ii)

Assume the population is approximately normal.

The 90% confidence interval for the mean µ of the population of female runners.

$(x^{-} - t_{\alpha } \frac{S}{\sqrt{n} } ,x^{-} +t_{\alpha } \frac{S}{\sqrt{n} } )$

substitute all above interval

$(65.80 - t_{\alpha } \frac{1.95}{\sqrt{12} } ,65.80 +t_{\alpha } \frac{1.95}{\sqrt{12} } )$

The degrees of freedom γ=n-1 = 12-1=11

From t- table = 1.363 at 90 % 0r 0.10 level of significance

$(65.80 -1.363 \frac{1.95}{\sqrt{12} } ,65.80 +1.363 \frac{1.95}{\sqrt{12} } )$

on calculation , we get

(65.80 -0.7672 ,65.80 + 0.7672)

( 65.0328 , 66.5672)

8 0

2 years ago

A travel website sells tickets to a city for two airlines. Among those buying tickets, 20% fly airline A, and 80% fly airline B.

Naddika [18.5K]

Answer:

The expected revenue of an airline ticket sold by this travel website is $408

Step-by-step explanation:

For the revenues per ticket we have;

airline A; 600

airline B; 360

For the probability of choosing the airlines we have;

airline A; 20% = 0.2

airline B; 80% = 0.8

Therefore, the expected revenue of an airline ticket sold by this travel website is;

600(0.2) + 360(0.8) = 408

Therefore, the expected revenue of an airline ticket sold by this travel website is $408

7 0

2 years ago

A rectangle or exercise mat has a perimeter of 48 feet the length of the mat Is twice The lift right and solve any questions to

Misha Larkins [42]

Answer:

The equation to determine the length is $4w+2w=48$ .

The Length of the exercise mat is 16 feet.

Step-by-step explanation:

Given:

Perimeter of Rectangular mat = $48\ ft$

Let the length of the mat be denoted by 'l'

And width be denoted by 'w'.

Also Given:

The length of the mat is twice the width of the mat.

So we can say that;

$l=2w$ ⇒ equation 1

Now we know that;

Perimeter of Rectangle is equal to twice the sum of length and width.

framing in equation form we get;

$2(l+w)=48$ ⇒ equation 2

Now Substituting equation 1 in equation 2 we get;

$2(2w+w)=48$

Applying Distributive property we get;

$2\times2w+2\times w=48\\\\4w+2w=48$

Hence, The equation to determine the length is $4w+2w=48$ .

On Solving the above equation we get;

$4w+2w=48\\\\6w=48$

Dividing both side by 6 we get;

$\frac{6w}{6}=\frac{48}{6}\\\\w=8\ ft$

Now Substituting the value of 'w' in equation 1 we get;

$l=2w=2\times8=16\ ft$

Hence The Length of the exercise mat is 16 feet.

3 0

2 years ago

Convert the following percent to a decimal: 56 percent.

mihalych1998 [28]

Answer:

0.56

Step-by-step explanation:

Percent means 'per 100'. So 56% means 56 per 100 or simply 56/100. If you divide 56 by 100, you'll get 0.56.

56/100 = 0.56

5 0

2 years ago

The product of -6 and a number increased by 2 is -40. Find the number.

Elan Coil [88]

The answer is -8 I know this as well as

4 0

3 years ago