Iliana signed up for a store credit card with no annual fee to get a discount of 12.5 percent off her entire first purchase.

An investor believes that investing in domestic and international stocks will give a difference in the mean rate of return. They

arlik [135]

Answer:

So on this case the 90% confidence interval would be given by $-4.137 \leq \mu_1 -\mu_2 \leq 2.087$

For this case since the confidence interval for the difference of means contains the 0 we can conclude that we don't have significant differences at 10% of significance between the two means analyzed.

Step-by-step explanation:

Previous concepts

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

$\bar X_1 =2.0233$ represent the sample mean 1

$\bar X_2 =3.048$ represent the sample mean 2

n1=15 represent the sample 1 size

n2=15 represent the sample 2 size

$s_1 =4.893387$ population sample deviation for sample 1

$s_2 =5.12399$ population sample deviation for sample 2

$\mu_1 -\mu_2$ parameter of interest at 0.1 of significance so the confidence would be 0.9 or 90%

We want to test:

H0: $\mu_1 = \mu_2$

H1: $\mu_1 \neq \mu_2$

And we can do this using the confidence interval for the difference of means.

Solution to the problem

The confidence interval for the difference of means is given by the following formula:

$(\bar X_1 -\bar X_2) \pm t_{\alpha/2}\sqrt{\frac{s^2_1}{n_1}+\frac{s^2_2}{n_2}}$ (1)

The point of estimate for $\mu_1 -\mu_2$ is just given by:

$\bar X_1 -\bar X_2 =2.0233-3.048=-1.0247$

The degrees of freedom are given by:

$df = n_1 +n_2 -2 = 15+15-2=28$

Since the Confidence is 0.90 or 90%, the value of $\alpha=0.1$ and $\alpha/2 =0.05$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-T.INV(0.05,28)".And we see that $t_{\alpha/2}=\pm 1.701$

Now we have everything in order to replace into formula (1):

$-1.0247-1.701\sqrt{\frac{4.893387^2}{15}+\frac{5.12399^2}{15}}=-4.137$

$-1.0247+1.701\sqrt{\frac{4.893387^2}{15}+\frac{5.12399^2}{15}}=2.087$

So on this case the 90% confidence interval would be given by $-4.137 \leq \mu_1 -\mu_2 \leq 2.087$

For this case since the confidence interval for the difference of means contains the 0 we can conclude that we don't have significant differences at 10% of significance between the two means analyzed.

4 0

2 years ago

What is the area of the triangle in the diagram?

dsp73

Answer:

The answer is the 2nd one

Step-by-step explanation:

5 0

2 years ago

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One of the formulas for calculating the correct dosage for a child is as follows: C= a/(a+12) ∙ 180

Brilliant_brown [7]

I'm assuming you're formula is "C=a/(a+12)*A" as that is only logical

You get the formula "C=a/(a+12)*A"

You insert the numbers given, in place of the letters given.

C=6/(6+12)*180
C=3*180
C=540 mg

Which is of course wrong because it is more than the adults dosage. What i'm trying to say is "Your formula is incorrect , follow the steps I gave, but use the correct formula"

5 0

2 years ago

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A remote control car races straight down the street at 26 miles per hour. Two

Pachacha [2.7K]

Answer:

It will take 4 hours for the second car to catch up with the first car.

Step-by-step explanation:

The first step to solving this problem is determining the difference in speed between the first and second car - you can see that the second car (at 52mph) is twice as fast as the first (26mph) therefore it will take half the time to cover the same distance.

As Car 1 has a 2 hour head start, it will be 52 miles ahead after 2 hours.

In the next 2 hours, Car 1 will travel 52 miles - so 104 in total after 4 hours, and car 2 will travel 104 miles, meaning that it will have caught up after 4 hours.

A)

To calculate distance per minute, divide the miles per hour by 60 (as there's 60 minutes in an hour), so:

Car 1 = 26/60 = 0.43 miles per minute

Car 2 = 52/60 = 0.867 miles per minute

To check your calculation, Car 2 should be exactly twice as far

B) The street, as far as we know, is at least 104 miles

C) See calculation at the top - the first car is 52miles from the start line when the second car starts

D) 2 cars are competing in this race

8 0

2 years ago

Mary’s yard is a mess. She needs to hire someone to prune her trees and shrubs. A landscaping service she calls quotes her a pri

IrinaK [193]

Answer:

I think it's C

Step-by-step explanation:

Maey should hire a landscaping service and if ther is more than 7.5h she could hire her neighbour

5 0

2 years ago

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