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Vlad [161]
1 year ago
9

Your start-up business is looking into the energy usage in the community of south lawndale. your sample size is 12 months. use t

he sample mean and standard deviation in killowatts (kwh) for the community south lawndale. what is the confidence interval at the 95% level?
Mathematics
1 answer:
Aleonysh [2.5K]1 year ago
5 0

The confidence interval at 95% level is

7106.87 <  μ< 14255.27

<h3>What is meant be mean and standard deviation?</h3>

The ratio of sum of observations to the total number of observation is known as mean. It is one of the central tendency in the statistics. It gives an idea about the central value present in the data. The most sensitive measure of central tendency is mean. It is very easy to calculate. Mean playa a crucial role in daily life. The two types of means are Arithmetic mean and Geometric mean.

Standard deviation is a measure in the statistics. The amount of variation of a set of values is known as standard deviation. Standard deviation is denoted by σ.

As per given data

90% confident level for amount of electricity used in community of Austin is

X-tx/2(n-1)s/√n < μ < X+ tx/2(n-1)s/√n

Here , n=12 ,  X=10681.07 , s=6893.87

Margin of error = tx/2(n-1)s/√n

=(1.796×6893.87)/√12

=3574.1996

=3574.19(approximately)

Therefore, 90% CI is,

10681.07-3574.19 ≤ μ<10681.07+3574.19

7106.87 <  μ< 14255.27

To know more about mean and standard deviation, visit:

brainly.com/question/14720855

#SPJ4

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Geometry
trapecia [35]

Answer:

EF = 8

Step-by-step explanation:

The following data were obtained from the question:

EF = 2x

FG = 8

EG = 4x

EF =?

To obtain the value of EF, we shall first, obtain the value of x. This can be obtained as follow:

EG = EF + FG

EF = 2x

FG = 8

EG = 4x

4x = 2x + 8

Collect like terms

4x – 2x = 8

2x = 8

Divide both side by 2

x = 8/2

x = 4

Therefore, the value of x is 4.

Finally, we shall determine the the value of EF as follow:

EF = 2x

x = 4

EF = 2x

EF = 2(4)

EF = 8

**** Check ****

EG = EF + FG

EF = 2x

EG = 4x

FG = 8

4x = 2x + 8

x = 4

4(4) = 2(4) + 8

16 = 8 + 8

16 = 16

4 0
3 years ago
There are two games involving flipping a coin. In the first game you win a prize if you can throw between 45% and 55% heads. In
Nina [5.8K]

Answer:

d) 300 times for the first game and 30 times for the second

Step-by-step explanation:

We start by noting that the coin is fair and the flip of a coin has a probability of 0.5 of getting heads.

As the coin is flipped more than one time and calculated the proportion, we have to use the <em>sampling distribution of the sampling proportions</em>.

The mean and standard deviation of this sampling distribution is:

\mu_p=p\\\\ \sigma_p=\sqrt{\dfrac{p(1-p)}{N}}

We will perform an analyisis for the first game, where we win the game if the proportion is between 45% and 55%.

The probability of getting a proportion within this interval can be calculated as:

P(0.45

referring the z values to the z-score of the standard normal distirbution.

We can calculate this values of z as:

z_H=\dfrac{p_H-\mu_p}{\sigma_p}=\dfrac{(p_H-p)}{\sqrt{\dfrac{p(1-p)}{N}}}=\sqrt{\dfrac{N}{p(1-p)}}*(p_H-p)>0\\\\\\z_L=\dfrac{p_L-\mu_p}{\sigma_p}=\dfrac{p_L-p}{\sqrt{\dfrac{p(1-p)}{N}}}=\sqrt{\dfrac{N}{p(1-p)}}*(p_L-p)

If we take into account the z values, we notice that the interval increases with the number of trials, and so does the probability of getting a value within this interval.

With this information, our chances of winning increase with the number of trials. We prefer for this game the option of 300 games.

For the second game, we win if we get a proportion over 80%.

The probability of winning is:

P(p>0.8)=P(z>z^*)

The z value is calculated as before:

z^*=\dfrac{p^*-\mu_p}{\sigma_p}=\dfrac{p^*-p}{\sqrt{\dfrac{p(1-p)}{N}}}=\sqrt{\dfrac{N}{p(1-p)}}*(p^*-p)>0

As (p*-p)=0.8-0.5=0.3>0, the value z* increase with the number of trials (N).

If our chances of winnings depend on P(z>z*), they become lower as z* increases.

Then, we can conclude that our chances of winning decrease with the increase of the number of trials.

We prefer the option of 30 trials for this game.

8 0
3 years ago
A man buys a book for Rs 400 and sells it for Rs 420 his profit is​
motikmotik

Answer:

20

Step-by-step explanation:

420-400=20

6 0
3 years ago
Read 2 more answers
A pizza parlor offers pizzas with diameters of 8 in, 10 in, and 12 in. find the area of each size pizza. round to the nearest te
MaRussiya [10]
Area od pizza, A = Pi*Diameter^2/4

A1 = Pi*8^2/4 = 50.27 in^2
A2 = Pi*10^2/4 = 78.54 in^2
A3 = Pi*12^2/4 = 113.10 in^2

Cost (C) per sq. in;
C1 = 50.27/9 = $5.59
C2 = 78.54/12 = $6.55
C3 = 113.10/18 = $6.28

The best buy is the first pizza with 8 in diameter as it costs the least per sq. inch.
3 0
3 years ago
Read 2 more answers
Catherine walks her dog 3/4 mile everyday how far does she walk each week
fenix001 [56]
Catherine walks her dog 5.25 miles because there are 7 days in one week and 3/4 x 7 = 5.25
5 0
3 years ago
Read 2 more answers
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