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andriy [413]
3 years ago
14

A simple random sample of 20 third-grade children from a certain school district is selected, and each is given a test to measur

e his/her reading ability. You are interested in calculating a 95% confidence interval for the population mean score. In the sample, the mean score is 64 points, and the standard deviation is 12 points.
What is the margin of error associated with the confidence interval?

A. 2.68 points

B. 4.64 points

C. 5.62 points

D. 6.84 point
Mathematics
1 answer:
ICE Princess25 [194]3 years ago
4 0

Answer:

Option C) 5.62 points  

Step-by-step explanation:

We are given the following in the question:

Sample size, n = 20

Sample mean score = 64

Sample standard deviation, s = 12

Degree of freedom =

=n-1\\=20-1\\=19

We have to calculate margin of error for a 95% confidence interval.

Formula for margin of error:

t_{critical}\times \displaystyle\frac{s}{\sqrt{n}}  

Putting the values, we get,  

t_{critical}\text{ at degree of freedom 19 and}~\alpha_{0.05} = \pm 2.093  

2.093\times (\displaystyle\frac{12}{\sqrt{20}} )\\\\ =5.6161\approx 5.62  

Thus, the correct answer is

Option C) 5.62 points

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Speeding: On a stretch of Interstate-89, car speed is a normally distributed variable with a mean of 69.1 mph and a standard dev
Alborosie

Answer: 11.9%

Step-by-step explanation:

Given :  On a stretch of Interstate-89, car speed is a normally distributed variable with \mu=69.1 mph and \sigma=3.3 mph.

Let x be a random variable that represents the car speed.

Since , z=\dfrac{x-\mu}{\sigma}

z-score corresponds x = 73 , z=\dfrac{73-69.1}{3.3}\approx1.18

Required probability :

\text{P-value }: P(x>73)=P(z>1.18)\\\\=1-P(z

[using z-value table.]

Hence, the approximate percentage of cars are traveling faster than you = 11.9%

8 0
3 years ago
If p varies jointly as q and r, and p = 150 when q = 18 and r = 5, find q when p = 345 and r = 9. TA​
hichkok12 [17]

Answer:

the answer is saltiness, why?

Step-by-step explanation:

because when i was little my bro used to ask me to go up and down with my mouth on his cucumber and i hated it but he offered me candy. Anyway now he gives me 5$ so ill do it more and as many times :D so i can get a new robucks card

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3 years ago
If f(x) = x/2 + 8, what is f(x) when x = 10?i
Triss [41]

Answer: f(x) = 13

Step-by-step explanation:

When x = 10

f(10) = 10/2 + 8

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= 13

Hope this helps!

6 0
3 years ago
Read 2 more answers
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Mkey [24]
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Hope this helps
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3 years ago
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You didn't provide a function that you are trying to maximize in this example, but the idea is that you take all of the (x,y) points which correspond to the vertices and plug them into your objective function. The one which produces the largest value maximizes it (it is a similar process for minimizing it, but you'd be looking for the smallest value). Let me know if you need more help than that, or would like me to work out the example you have provided (I will need an objective function for it though).
6 0
3 years ago
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