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shtirl [24]
3 years ago
12

PLEASE ANSWER PLEASE! I

Mathematics
1 answer:
GaryK [48]3 years ago
6 0

Answer:

4.45454545455  

=4.45

Step-by-step explanation:

so yeah your right just put a bar under 45 like this,,,,

4.<u>45</u>

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An environmental group conducted a study to determine whether crows in a certain region were ingesting food containing unhealthy
nydimaria [60]

Part A

Given info:

  • xbar = sample mean = 4.90 ppm
  • s = sample standard deviation = 1.12 ppm
  • n = 23 = sample size

Because n > 30 is not true, and we don't know the population standard deviation (sigma), this means we must use a T distribution.

The degrees of freedom here are n-1 = 23-1 = 22.

At 90% confidence and the degrees of freedom mentioned, the t critical value is roughly t = 1.717

Use a T distribution table or calculator to determine this. If you don't have a calculator for the task, then you can search out "inverse T calculator" and there are tons of free options to pick from.

The margin of error E is

E = t*s/sqrt(n)

E = 1.717*1.12/sqrt(23)

E = 0.400982

This is approximate and accurate to 6 decimal places.

The confidence interval is going to be xbar plus or minus that E value

L = lower bound = xbar - E = 4.90 - 0.400982 = 4.499018 = 4.50

U = upper bound = xbar + E = 4.90 + 0.400982 = 5.300982 = 5.30

The confidence interval in the format of (L, U) is (4.50, 5.30)

You could also express it as the format L < mu < U and it would be 4.50 < mu < 5.30; however, I'll stick to the first method.

<h3>Answer:  (4.50, 5.30)</h3>

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

Part B

Since we know sigma = 2.6 is the population standard deviation, we can use a Z distribution now.

At 90% confidence, the z critical value is roughly 1.645; use a table or calculator to determine this.

n = \left(\frac{z*\sigma}{E}\right)^2\\\\n \approx \left(\frac{1.645*2.6}{0.03}\right)^2\\\\n \approx 20325.254444 \\\\

Round this up to the nearest integer to get 20326. For min sample size problems, <u>always</u> round up.

<h3>Answer: 20326</h3>
6 0
2 years ago
Which situation can be modeled by the expression-12 x 1/3?
fomenos

Answer:hehdhfhdhd

Step-by-step explanation:

Hdhdhhs

7 0
3 years ago
Three times a certain number is 21. What is the number?
Goshia [24]

Answer:

The answer is 7

Step-by-step explanation:

an easier way to think of it is 21 divided by 3, which again, is 7.

Hope That Helps!

7 0
3 years ago
Read 2 more answers
Help me please i’ll rate brainliest
Cloud [144]

Answer:

<em>- 1.568</em>  

Step-by-step explanation:

Let's assume that the base of the given logarithm is 10.

log m = 0.345 ⇒ 10^{0.345} = m

log n = 1.223 ⇒ 10^{1.223} = n

mn = 10^{0.345} × 10^{1.223} = 10^{1.568}

\frac{1}{mn} = 10^{-1.568}

log 10^{-1.568} = - 1.568 × log 10 = <em>- 1.568</em>

5 0
3 years ago
Add −1.5+1.75<br><br> Plot the first addend and the sum on the number.
jek_recluse [69]

Answer:

0.5+0.75=0.80

now

1+1=2

2+0.80=2.89

6 0
2 years ago
Read 2 more answers
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