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Brilliant_brown [7]

3 years ago

11

I need help is it A B C or D

1 answer:

babymother [125]3 years ago

4 0

The answer A because I did the math and y is -20 and x is -12

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The authors of a paper describe an experiment to evaluate the effect of using a cell phone on reaction time. Subjects were asked

Serggg [28]

Answer:

a) The 99% confidence interval would be given by (24.409;24.979)

b) n=464

Step-by-step explanation:

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".

Part a

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:

$df=n-1=47-1=46$

Since the Confidence is 0.95 or 95%, the value of $\alpha=0.05$ and $\alpha/2 =0.025$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-T.INV(0.025,46)".And we see that $t_{\alpha/2}=2.01$

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

$525-2.01\frac{75}{\sqrt{47}}=503.01$

$525+2.01\frac{75}{\sqrt{47}}=546.99$

So on this case the 95% confidence interval would be given by (503.01;546.99)

Part b

The margin of error is given by this formula:

$ME=t_{\alpha/2}\frac{s}{\sqrt{n}}$ (1)

And on this case we have that ME =7 msec, we are interested in order to find the value of n, if we solve n from equation (1) we got:

$n=(\frac{t_{\alpha/2} s}{ME})^2$ (2)

The critical value for 95% of confidence interval is provided, $t_{\alpha/2}=2.01$ from part a, replacing into formula (2) we got:

$n=(\frac{2.01(75)}{7})^2 =463.79 \approx 464$

So the answer for this case would be n=464 rounded up to the nearest integer

8 0

3 years ago

Find the value of the combination.<br><br> 5C5<br><br> A:1<br> B:5<br> C:0

Olenka [21]

Answer:

A:1

Step by step explanations:

C(n,r)=C(5,5)

n=5

r=5

=n! / (r!(n-r)!)

=5! / (5!(5-5)!)

=1

6 0

3 years ago

A wagon train on the Oregon Trail averaged 17.3 miles each day across the plains. How far was the wagon train able to travel in

Makovka662 [10]

17.3 x 7 = 121.1 per week

121.1 x 4 = 484.4

5 0

3 years ago

Read 2 more answers

Natalia is moving into a new house. All together, her furniture weighs 3,204 pounds. If it takes 8 trucks to carry all of Natali

Allisa [31]

Answer:

D

Step-by-step explanation:

The average can be found by dividing the number of pieces (or trucks in this case) by the total, so 3204/8=400.5 pounds, or D as our answer

6 0

3 years ago

What is the volume of the box pictured below?

SpyIntel [72]

Answer:

The volume of the box is 3/4 cubic meters.

Step-by-step explanation:

We know that volume = length * width * height. We have length, width, and height already, so all we have to do is multiply.

5/6 * 1 1/8 * 4/5. First we convert 1 1/8 from a mixed fraction, to give us 9/8, as 8/8 = 1.

5/6 * 9/8 * 4/5. 5 * 9 = 45, and 6 * 8 = 48. 45/48 reduces to 15/16.

15/16 * 4/5. 15 * 4 = 60, and 16 * 5 = 80. 60/80 reduces to 6/8, which reduces to 3/4.

8 0

3 years ago

Read 2 more answers