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AlexFokin [52]
2 years ago
15

Pls help Ill give brainiest or whatever

Mathematics
2 answers:
frutty [35]2 years ago
8 0

Answer:

The time is 2.5 hours.

Step-by-step explanation:

7.5/3=2.5

hope this helps!

Contact [7]2 years ago
4 0

Answer:

2.5 hours

Step-by-step explanation:

it takes him 2.5 hours

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2. To estimate the mean age for a population of 4000 employees, a simple random sample of 40 employees is selected. a. Would you
ANEK [815]

Answer:

Step-by-step explanation:

a.

Size of the population, N = 4000

Size of the sample, n = 40

n/N = 40/4000 = 0.01

0.01 is less than 0.05 and hence we would not us the finite population correction factor in calculating the standard error of the mean.

b.

Population standard deviation is σ = 8.2

<u>So, the standard error of x’ using the finite population correction factor is give by</u>

σ(x’) = √[(N - n)/(N - 1)] x (sigma/√n)

σ(x’) = √[(4000 - 40)/(4000 - 1)] x (8.2/√40)

σ(x’) = 1.29

<u>Standard error of x’ without using the finite population correction factor is</u>

σ(x’) = σ/√n

σ(x’) = 8.2/√40 = 1.2965

<u>There is little difference between the two values of the standard error. So we can ignore the population correction factor.</u>

c.

Let the population mean be μ

Probability that the sample mean will be within =-2 of the population mean is

P(μ– 2 < x’ < μ + 2)

At x’ = μ – 2 , we have

z = (μ – 2 – μ)/1.2965

z = -1.54

at x’ = μ  + 2, we have

z = (μ + 2 – μ)/1.2965

z = 1.54

<u>So the required probability is </u>

P(μ – 2 < x’ < μ + 2) = p(-1.54< z < 1.54)

P(μ – 2 < x’ < μ + 2) = p(z < 1.54) – p(z < -1.54)

P(μ – 2 < x’ < μ + 2) = 0.9382 – 0.0618

P(μ – 2 < x’ < μ + 2) = 0.8764

7 0
3 years ago
25. Which is an example of an operation?<br> A) 12<br> B) 6ab<br> C) +<br> D) y
nasty-shy [4]
Letter c is an operation.
Addition
8 0
3 years ago
Agree or desagree ? short question ​
Dafna11 [192]

Answer:

Disagreee

Step-by-step explanation:

it has 6 sides so take 360/6 and you'll get 60, so it has to be rotated 60deg for it to be carried onto itself.

6 0
2 years ago
What is three and one third plus four and one third equals
prohojiy [21]

Answer:

7 2/3

Step-by-step explanation:

3 0
2 years ago
There are 24 chairs in the art room. What are the
pentagon [3]

Answer:

12 in each row (2 rows)

6 in each row (4 rows)

4 in each row (6 rows)

2 in each row (12 rows)

8 in each row (3 rows)

3 in each row (8 rows)

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