PLEASE HELP MEEE Instruction

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

2 years ago

Find the exact value of tan22.5 using the half angle formula.

mote1985 [20]

Tan(a/2) = sin a / (1 + cos a)
tan(45/2) = sin(45) / (1 + cos(45)) = (1/√2) / (1 + 1/√2) = (1/√2) / (√2 + 1)/√2 = 1/(√2 + 1) = (√2 - 1)

7 0

2 years ago

Read 2 more answers

What is the Absoulte value of 3

aleksandr82 [10.1K]

Answer:

it's 3

Step-by-step explanation:

Number 3 is 3 units away from 0, and thus the absolute value of 3 is 3.

3 0

2 years ago

A store sells mugs. Each mug costs the same amount. During a sale, the store reduces the price of each mug by $1.75. Wen spends

Sergio039 [100]

I’m assuming the question is what is the price of one mug WITHOUT the sale.

So since the price of 5 mugs is $28.20, we can work out the price of one mug with the sale.

We do this by doing:

$28.20 / 5

Which gives us:

$5.64 per mug during the sale.

To work out the price of a mug without the sale, we simply add on the amount that has been taken off (which we know is $1.75 because the question says so):

$5.64 + $1.75 = $7.39

Therefore we can conclude the price of a mug without a sale is $7.39

And the price of a mug during the sale is $5.64.

I hope this helps!

8 0

2 years ago

What is the row echelon form of this matrix?

USPshnik [31]

The row echelon form of the matrix is presented as follows;

$\begin{bmatrix}1 &-2 &-5 \\ 0& 1 & -7\\ 0&0 &1 \\\end{bmatrix}$

<h3>What is the row echelon form of a matrix?</h3>

The row echelon form of a matrix has the rows consisting entirely of zeros at the bottom, and the first entry of a row that is not entirely zero is a one.

The given matrix is presented as follows;

$\begin{bmatrix}-3 &6 &15 \\ 2& -6 & 4\\ 1&0 &-1 \\\end{bmatrix}$

The conditions of a matrix in the row echelon form are as follows;

There are row having nonzero entries above the zero rows.
The first nonzero entry in a nonzero row is a one.
The location of the leading one in a nonzero row is to the left of the leading one in the next lower rows.

Dividing Row 1 by -3 gives:

$\begin{bmatrix}1 &-2 &-5 \\ 2& -6 & 4\\ 1&0 &-1 \\\end{bmatrix}$