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ad-work [718]
4 years ago
10

A researcher wants to know if the average time in jail for robbery has increased from what it was when the average sentence was

7 years. he obtains data on 400 more-recent robberies and finds an average time served of 7.5 years. find a 95% confidence interval for the average time served (assume jail time follows a normal distribution with standard deviation 3 years).
Mathematics
1 answer:
kati45 [8]4 years ago
5 0

At 95% confidence interval, the z score is 1.96. Using the formula:

Confidence Interval = x ± z s / sqrt (n)

where x is the average time served, s is standard deviation and n is number of samples

 

Confidence interval = 7.5 ± (1.96 * 3) / sqrt (400)

Confidence interval = 7.5 ± 0.294

<span>Confidence interval = 7.206 to 7.794</span>

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What is the number of solutions in this system?
Nana76 [90]

Answer:

No solution.

Step-by-step explanation:

Since the solution lies on three distinct planes.

Regards: Umer

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4 years ago
Kodie had to write 6 pages for a book report. How many hours would it take him to write it if he wrote one-seventh of a page eac
34kurt

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8 hours? sorry if im wrong

Step-by-step explanation:

4 0
3 years ago
A set of test scores are normally distributed. The mean is 100 and the standard deviation is 20. These scores are converted to s
Whitepunk [10]

Answer:

The z-scores of both the mean and the median are zero.

Step-by-step explanation:

In a normal distribution, the mean and median values will be the same, in this case, 100. Therefore, both the mean and median will have the same score.

The z-score is given by:

z=\frac{X-\mu}{\sigma}

For X = 100:

z=\frac{100-100}{20}\\ z=0

The z-scores of both the mean and the median are zero.

5 0
3 years ago
Suppose U= {1, 2, 3, 4, 5, 6, 7, 8} is the universal set and P= {1, 2, 3, 4}. What is P?
Digiron [165]
Did you mean P' ? The letter P with a tick mark after it. If so, then start with set U and erase any number you find in set P

We start with 
{1,2,3,4,5,6,7,8}
and we erase the following: 1,2,3,4
since those numbers are in set P

P = {1,2,3,4}
P ' = {5, 6, 7, 8}

<span>The set P' is the complement of set P. It is, in a sense, the opposite of set P. It contains everything that P doesn't have.</span>
4 0
3 years ago
Karla saved 2/3 of her allowance. Olga saved 25% of her allowance. Harley saved 1/8 of her allowance. And, Kayla saved 0.40 of h
Fittoniya [83]

Answer:

0.125, 0.25, 0.4, 0.666...

Harley, Olga, Kayla, Karla

Step-by-step explanation:

Change each number into a decimal, then compare them.

Karla saved 2/3 = 0.666...

Olga saved 25% = 0.25

Harley saved 1/8 = 0.125

Kayla saved 0.40 = 0.4

From least to greatest:

0.125, 0.25, 0.4, 0.666...

Harley, Olga, Kayla, Karla

3 0
2 years ago
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