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3 years ago

How many presedents do we have in the united states of america

2 answers:

8 0

To answer your question very literally, the united states only elects one president per term! The president can only serve two terms and is then forced to leave office! But if you where asking how many presidents the U.S. has had, as of 2016 the U.S. has had exactly 43 presidents and 44 presidencies (one served a second term)

kipiarov [429]3 years ago

5 0

44 is the number of presidents we have had in the united states

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Question 9 of 10

denis-greek [22]

The answer should be A and D

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2 years ago

The original price of an audio jukebox was 280 it is on sale for 220 what percent discount does this represent

solong [7]

Answer:

The answer would be 12%

Step-by-step explanation:

250-220=30 and 30 is 12% of 250

4 0

2 years ago

Read 2 more answers

The perimeter of a triangle is 105. the lengths of all three sides are represented by three consecutive odd integers. Find the l

aev [14]

The longest side of the triangle is 37.

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3 years ago

1.In the diagram of circle M shown, various points are located on the circle as shown.   a) List three segments that are radii o

dalvyx [7]

Answer:

(a)|MA|, |MB| and |MC|

(b) |BD|

Step-by-step explanation:

An adapted diagram of this question is attached. You can vary the labelled letters as required.

Definition

A radius is a line drawn from the center of a circle to its circumference.
A segment is a line that connects two points.
A diameter is a chord which passes through the center of the circle.
A chord is any line joining two points on the circles' circumference.

By these definitions:

(a)Segments that are radii of this circle.

We have: |MA|, |MB| and |MC|

(b)Segment that is a diameter of this circle.

|BD|

(c)A chord of this circle that is not a diameter.

|BC|

3 0

2 years ago

An experiment to investigate the survival time in hours of an electronic component consists of placing the parts in a test cell

mixer [17]

Answer:

a) The sample mean is of 49 and the sample standard deviation is of 11.7.

b) The range of the true mean at 90% confidence level is of 9.62 hours.

c) The prediction interval, at a 90% confidence level, of it's failure time is between 39.38 hours and 58.62 hours.

Step-by-step explanation:

Question a:

Sample mean:

$\overline{x} = \frac{34+40+46+49+61+64}{6} = 49$

Sample standard deviation:

$s = sqrt{\frac{(34-49)^2+(40-49)^2+(46-49)^2+(49-49)^2+(61-49)^2+(64-49)^2}{5}} = 11.7$

The sample mean is of 49 and the sample standard deviation is of 11.7.

b)Determine the range of the true mean at 90% confidence level.

We have to find the margin of error of the confidence interval. Since we have the standard deviation for the sample, the t-distribution is used.

The first step to solve this problem is finding how many degrees of freedom, we have. This is the sample size subtracted by 1. So

df = 6 - 1 = 5

90% confidence interval

Now, we have to find a value of T, which is found looking at the t table, with 5 degrees of freedom(y-axis) and a confidence level of $1 - \frac{1 - 0.9}{2} = 0.95$ . So we have T = 2.0.150

The margin of error is:

$M = T\frac{s}{\sqrt{n}}$

In which s is the standard deviation of the sample and n is the size of the sample. So

$M = 2.0150\frac{11.7}{\sqrt{6}} = 9.62$

The range of the true mean at 90% confidence level is of 9.62 hours.

(c)If a seventh sample is tested, what is the prediction interval (90% confidence level) of its failure time.

This is the confidence interval, so:

The lower end of the interval is the sample mean subtracted by M. So it is 49 - 9.62 = 39.38 hours.

The upper end of the interval is the sample mean added to M. So it is 49 + 9.62 = 58.62 hours.

The prediction interval, at a 90% confidence level, of it's failure time is between 39.38 hours and 58.62 hours.

4 0

2 years ago