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alina1380 [7]
3 years ago
9

Denise is a professional swimmer who trains, in part, by running. she would like to estimate the average number of miles she run

s in each week. for a random sample of 20 weeks, the mean is = 17.5 miles with standard deviation s = 3.8 miles. find a 99% confidence interval for the population mean number of miles denise runs. use a graphing calculator for this one and not the t chart from the book.
Mathematics
1 answer:
SSSSS [86.1K]3 years ago
4 0
Given:
n = 20, sample size
xbar = 17.5, sample mean
s = 3.8, sample standard deiation
99% confidence interval

The degrees of freedom is 
df = n-1 = 19

We do not know the population standard deviation, so we should determine t* that corresponds to df = 19.
From a one-tailed distribution, 99% CI means using a p-value of 0.005.
Obtain
t* = 2.8609.

The 99% confidence interval is
xbar +/- t*(s/√n)

t*(s/√n) = 2.8609*(3.8/√20) = 2.4309
The 99% confidence interval is
(17.5 - 2.4309, 17.5 + 2.4309) = (15.069, 19.931)

Answer: The 99% confidence interval is (15.07, 19.93)
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At a restaurant, 25% of the dinner plates are clean. There are 80 total dinner
pochemuha

Answer:

20

Step-by-step explanation:

7 0
3 years ago
Describe and correct the error in finding the tenth term of the arithmetic sequence 4, 12, 20, 28.
ycow [4]

Answer: The tenth term is 76

=======================================================

Explanation:

We use this arithmetic sequence formula to get the nth term

a_n = a_1 + d(n-1)

Plug in a_1 = 4, \ d = 8, \ n = 10 and you should get the following:

a_n = a_1 + d(n-1)\\\\a_{10} = 4 + 8(10-1)\\\\a_{10} = 4 + 8(9)\\\\a_{10} = \textbf{76}\\\\

The tenth term is <u>76</u>

---------

We can verify this by listing out the terms one by one. Start at 4, add on 8 each time, until you generate the 10th term. A table like the one shown below is a good way to keep track of all the terms.

\begin{array}{c|c}\boldsymbol{n} & \boldsymbol{a_n}\\1 & 4\\2 & 12\\3 & 20\\4 & 28\\5 & 36\\6 & 44\\7 & 52\\8 & 60\\9 & 68\\10 & \textbf{76}\\\end{array}

---------

In short, the error is with the "10" in the expression 4+10(8). The student should have used 9 instead. This is because of the n-1 term in a_n = a_1 + d(n-1) which shifts everything one spot to the left.

7 0
2 years ago
Solve for x<br>8x - 20 4x + 32​
Alenkinab [10]

Answer:

13

Step-by-step explanation:

8x - 20 = 4x + 32​ ( F rule angles)

8x-4x=32+20

4x=52

x=52/4

x=13

7 0
2 years ago
Need help!!! I dont get it
lesya692 [45]

Answer:

4/3π - √3

Step-by-step explanation:

Pie piece of circle is area of circle x portion of circle

πr²*x/360 = π(2)²*120/360 = 4/3π

Then you must subract the non-right triangle area

1/2ab sin C = 1/2(2)(2) sin 120 = 2 * √3/2 = √3

4/3π - √3

7 0
2 years ago
Evaluate the expression.<br><br> ║4/13║
NNADVOKAT [17]

Answer:

4/13

Step-by-step explanation:

In absolute value, it is showing distance. Whenever something is in absolute value, it is turned positive.

here, Inside the absolute value brackets, we have positive 4/13. Positive 4/13 undergoes no such change, because there are no other terms, and no negatives.

absolute value of 4/13 is 4/13

7 0
3 years ago
Read 2 more answers
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