I’m confused. Can you help

We considered the differences between the temperature readings in January 1 of 1968 and 2008 at 51 locations in the continental

mr Goodwill [35]

Answer:

$1.1-2.02\frac{4.9}{\sqrt{50}}=-0.30$

$1.1+2.02\frac{4.9}{\sqrt{50}}=2.50$

So on this case the 90% confidence interval would be given by (-0.30;2.50)

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".

$\bar X=1.1$ represent the sample mean for the sample

$\mu$ population mean (variable of interest)

s=4.9 represent the sample standard deviation

n=51 represent the sample size

Solution to the problem

The confidence interval for the mean is given by the following formula:

$\bar X \pm t_{\alpha/2}\frac{s}{\sqrt{n}}$ (1)

In order to calculate the critical value $t_{\alpha/2}$ we need to find first the degrees of freedom, given by:

$df=n-1=51-1=50$

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(0.05,50)".And we see that $t_{\alpha/2}=2.02$

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

$1.1-2.02\frac{4.9}{\sqrt{50}}=-0.30$

$1.1+2.02\frac{4.9}{\sqrt{50}}=2.50$

So on this case the 90% confidence interval would be given by (-0.30;2.50)

8 0

3 years ago

Juana is 4 feet 8 inches tall. She won 1st place in a cross country race. To receive her medal she stood on a platform that was

ioda

Answer:

The distance from the top of her head to the floor is 6 feet 2 inches.

Step-by-step explanation:

In his case Juana's height is given to us with two kinds of units, feet and inches, in order to make our solution easyer we will transform her height to only inches. In 1 feet we have 12 inches, so we need to take the part of her height that is given in feet and multiply it by 12. We have:

height = 4*12 + 8 = 56 inches

Since she is in a platform that is 18 inches tall the distance from the top of her head to the floor is her height plus the height of the platform. We have:

distance = height + platform = 56 + 18 = 74 inches

We can now transform back to a mixed unit, we do that by dividing the distance by 12 that will be the "feet" part and the res of the division will be the "inches" part. We have:

distance = 74/12 = 6 feet 2 inches

The distance from the top of her head to the floor is 6 feet 2 inches.

6 0

3 years ago

You recently purchased a new snowboard for the upcoming winter. The board, with bindings, came out to be $315.32. You were told

gizmo_the_mogwai [7]

First the original price is reduced by 15%
assume the original price is x
100%-15%=85%..u r left with 85% of the price
thus,85/100 multiply x
the reduced price is reduced again by 5%
so,95/100 ×(85/100 x)=$315.32
find x
323/400 x =$315.32
×=$390.49

7 0

3 years ago

john is looking at a map with a scale of 1/4 inch=20 miles. he measured the distance from his home to the bowling alley in town

Sergio039 [100]

1 inch=80mi

2.5*80mi=200 mi

5 0

3 years ago

63-28=subtracting by adding up

Tresset [83]

Answer:

35

Step-by-step explanation:

7 0

4 years ago