A track coach wants to know how good the runners on another team are.

The branch manager of an outlet (Store 1) of a nationwide

monitta

Answer:

1. ( 19.1416, 23.5384,)

2. (0.276348, 0.46651)

3. the sample size = 170.73 approximately 171

4. sample size = 334.07 approximately 334

5. sample of 334 should be taken by manager

Step-by-step explanation:

mean = bar x = 21.34 dollars

size of sample n = 70

standard deviation of sample = 9.22

we use t distribution as the population standard deviation is not known.

95% Confidence interval

1-α = 0.95

α = 0.05

degree of freedom = 70-1 = 69

α/2 = 0.025

using the t distribution tsble,

= 1.9949

confidence interval = $21.34+-1.9949*[\frac{9.22}{sqrt(70)}] \\$

= 21.34 +- (1.9949*1.10200)

= 21.34 + 2.1984, 21.34 - 2.1984

= (23.5384, 19.1416)

the confidence interval of the mean amount spent at the supply store can be written as 19.1416<u<23.5384

2. sixe of those who only have a cat

p = 26/70 = 0.371429

at 90 % confidence interval,

1-α = 0.90

α = 0.10

we use the z table here

z(0.10/2) = Z(0.05)

= 1.645

$0.371429+-1.645\sqrt} \frac{0.371429(1-0.371429)}{70}$

= 0.371429 +-( 1.645 x 0.0578)

= 0.371429 + 0.095081, 0.371429 - 0.095081

= (0.276348, 0.46651)

3. sd = 10$

margin of erro,r e = 1.50$

α = 0.05

using z table

α/2 = Z0.025

= 1.96

sample size = 1.96² * 10² / 1.50²

= 3.8416 * 100/ 2.25

= 170.73

the sample size is approximately 171

d. we have 0.5 as sample proportion now

margin of error = 0.045

α = 0.10

Zα/2 = 0.05

= 1.645

sample size = 1.645²x0.5(1-0.5) / 0.045²

= 0.676506/0.002025

= 334. 07

sample size = 334

5. sample of 334 should be taken by manager

3 0

3 years ago

Each sister bought a gift for their mom. Maggie spent 3 times as much as Karen. Karen spent half as much as Jasmine. Altogether,

snow_tiger [21]

Answer:

Maggie spent =30

Karen spent = 10

Jasmine spent =20

Step-by-step explanation:

In this we use algebra to solve.we give the sisters unknowns, to help us solve the equation.

we dont know how much jasmine used so we give her the unknown x.you can use any letter but ill us x.

karen used half as much as karen so we give her 1/2x because it was half of jasmine.maggie used 3 times that of karen so w give her 3(1/2x).

maggie =3(1/2x)

Karen =1/2x

jasmine =x

3(1/2x) + 1/2x + x = 60

3/2x + 1/2x + x = 60

2x + x = 60

3x=60

x=20

where we have x =we replace with 20

e.g karen 1/2x => 1/2 x 20 =10

if you need any clarifications please do tell me in the comment section.i would like to help more if you need help.thx

Hope this helps and if it does mark as branliest anwer thx

6 0

2 years ago

A business executive bought 40 stamps for

alekssr [168]

Answer:

32 33-cent stamps, 8 23-cent stamps

Step-by-step explanation:

In order to solve this question, we need to set up a system of equations. Also known as solving for two variables (the number of each stamp).

Let's set x to be the number of 33-cent stamps. Similarly, let's set y to be the number of 23-cent stamps.

To make our first equation, let's think about the number of stamps total we have. We can say:

$x + y =40$

(AKA - The number of 33-cent stamps, plus the number of 23-cent stamps, equals 40 stamps.)

Now, let's make an equation for the cost of these stamps.

$0.33x + 0.23y = 12.40$

(AKA - The cost of the stamps in total, should equal $12.40).

So now, we have our two equations:

$x + y =40\\0.33x+0.23y=12.40$

If you have a TI-84 graphing calculator, you can go to apps -> polysmlt2 -> simultaneous eqn solver, and then input these equations into the menu. This will solve the problem for you.

If you need to do this manually, let's use substitution. Condense our first equation to make it more substitutable.

$x+y=40\\x=40-y$

Now, let's put this into our second equation.

$0.33x+0.23y=12.40\\0.33(40-y)+0.23y=12.40$

Distribute, and solve for y.

$13.2-0.33y +0.23y =12.40\\13.2-0.1y=12.40\\-0.1y=-0.8\\y=8$

Now, we plug this into one of our equations.

$x+y=40\\x+8=40\\x=32$

In the end, we have thirty-two 33-cent stamps, and eight 23-cent stamps.

3 0

1 year ago

. There are 11 boys and 5 girls that tried out to

Lisa [10]

We want to find the probability that the two students chosen for the duet are boys. We will find that the probability that both students chosen for the duet are boys is 0.458

If we assume that the selection is totally random, then all the students have the same probability of being chosen.

This means that, for the first place in the duet, the probability of randomly selecting a boy is equal to the quotient between the number of boys and the total number of students, this is:

P = 11/16

For the second member of the duet we compute the probability in the same way, but this time there is one student less and one boy less (because one was already selected).

Q = 10/15

The joint probability (so both of these events happen together) is just the product of the individual probabilities, this will give:

Probability = P*Q = (11/16)*(10/15) = 0.458

So the probability that both students chosen for the duet are boys is 0.458

If you want to learn more, you can read:

brainly.com/question/1349408

5 0

2 years ago

I will give brainly help.

Burka [1]

Answer:

Company G charges 5 more dollars per hour than Company H.