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Nina [5.8K]
2 years ago
7

In 2014, 85 percent of households in the United States had a computer. For a randomly selected sample of 200 households in 2014,

let the random variable C represent the number of households in the sample that had a computer. What are the mean and standard deviation of C ?
Mathematics
2 answers:
DochEvi [55]2 years ago
7 0

Answer:

The mean of C is 170 households

The standard deviation of C, is approximately 5 households

Step-by-step explanation:

The given parameters are;

The percentage of households in the United States that had a computer in 2014 = 85%

The size of the randomly selected sample in 2014, n = 200

The random variable representing the number of households that had a computer = C

Therefore, we have;

The probability of a household having a computer P = 85/100 = 0.85

Let

Therefore;

The mean (expected) number in the sample, μₓ, = E(x) = n × P is given as follows;

μₓ = 200 × 0.85 = 170

The mean of C = μₓ = 170

The variance, σ² = n × P × (1 - P) = 200 × 0.85 × (1 - 0.85) = 25.5

Therefore;

The standard deviation, σ = √(σ²) = √(25.5) ≈ 5.05

The standard deviation of C, σ ≈ 5 households (we round (down) to the nearest whole number)

pickupchik [31]2 years ago
5 0

Answer:

The mean is 170 households, and the standard deviation is 5.05 households.

Step-by-step explanation:

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pshichka [43]

Answer:

An adult Welsh Corgi is always going to be shorter than an adult Basset Hound.

Step-by-step explanation:

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whichever just not the other ones good luck!

8 0
2 years ago
C. Assessment
Crazy boy [7]
1. B
2. A
3. A
All of theses are true
4 0
2 years ago
A juice drink filling machine, when in perfect adjustment, fills the bottles with 12 ounces of drink on an average. Any overfill
ozzi

Answer:

d. The average is equal to 12 ounces.

Step-by-step explanation:

In this problem, the drink filling machine must be perfectly calibrated at 12 ounces since it needs to be shut down in cases of overfilling (mean > 12 ounces) and underfilling (mean < 12 ounces). Therefore, the correct approach would be to test if the mean is 12 ounces and the correct set of hypothesis would be:

H_0:\mu=12\\H_a:\mu\neq 12

The correct alternative is d. The average is equal to 12 ounces.

5 0
2 years ago
A spherical scoop of ice cream is placed on top of a hollow ice cream cone. the scoop and cone have the same radius. the ice cre
noname [10]
The figure shown below illustrates the problem.

The volume of the empty cone is
V₁ = (1/3) π r²h

The volume of the sphere is
V₂ = (4/3) π r³

Because the melted ice cream completely fills the cone, therefore
V₁ = V₂
(1/3) π r² h = (4/3) π r³
Divide each side by (1/3) π r².
h = 4r

Answer:
The height of the cone is 4 times greater than the radius f the cone.

5 0
2 years ago
The number of "destination weddings" has skyrocketed in recent years. For example, many couples are opting to have their wedding
Andru [333]

Answer:

There is no sufficient evidence to support the claim that wedding cost is less than $30000.

Step-by-step explanation:

Values (x) ∑(Xi-X)^2

----------------------------------

29.1                    0.1702

28.5                  1.0252

28.8                  0.5077

29.4                   0.0127

29.8                  0.0827

29.8                  0.0827

30.1                   0.3452

30.6                   1.1827

----------------------------------------

236.1                 3.4088

Mean = 236.1 / 8 = 29.51

S_{x}=\sqrt{3.4088/(8-1)}=0.6978

Statement of the null hypothesis:

H0: u ≥ 30 the mean wedding cost is not less than $30,000

H1: u < 30 the mean wedding cost is less than $30,000

Test Statistic:

t=\frac{X-u}{S/\sqrt{n}}=\frac{29.51-30}{0.6978/\sqrt{8}}= \frac{-0.49}{0.2467}=-1.9861

Test criteria:

SIgnificance level = 0.05

Degrees of freedom = df = n - 1 = 8 - 1 = 7

Reject null hypothesis (H0) if

t

Finding in the t distribution table α=0.05 with df=7, we have

t_{0.05,7}=2.365

t>-t_{0.05,7} = -1.9861 > -2.365

Result: Fail to reject null hypothesis

Conclusion: Do no reject the null hypothesis

u ≥ 30 the mean wedding cost is not less than $30,000

There is no sufficient evidence to support the claim that wedding cost is less than $30000.

Hope this helps!

5 0
2 years ago
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