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Lady bird [3.3K]
3 years ago
14

The commute time to work in the U.S. Has a bell shaped distribution with a population mean of 24.4 minutes and a population stan

dard deviation of 6.5 minutes. What proportion of the population has a commute time: a) between 11.4 minutes and 37.4 minutes? (1 pt) b) less than 11.4 minutes? (1 pt) c) greater than 37.4 minutes? (1 pt)
Mathematics
1 answer:
Alexxx [7]3 years ago
5 0

Answer:

1. 0.9544

2. 0.0228

3. 0.0228

Step-by-step explanation:

The computation is shown below;

As we know that

At Normal distribution

P(X < A) = P(Z < \frac{(A - mean)}{standard deviation})

As per the question, the data provided is as follows

Mean = 24.4 minutes

Standard deviation = 6.5 minutes

Based on the above information

P(11.4 < X < 37.4) = P(X < 37.4) - P(X < 11.4)

= P(Z < (37.4 - 24.4) ÷ 6.5) - P(Z < (11.4 - 24.4) ÷ 6.5)

= P(Z < 2) - P(Z < -2)

= 0.9772 - 0.0228

= 0.9544

2. P(X < 11.4) = 0.0228

3. P(X ≥ 37.4) = 1 - P(X < 37.4)

= 1 - 0.9772

= 0.0228

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38. Calculate the value of c in the triangle below.
olchik [2.2K]

Answer:

15

Step-by-step explanation:

a^2 + b^2 = c^2

9^2 + 12^2 = 225

\sqrt{225}  = 15

Hope this helps!!

7 0
2 years ago
Read 2 more answers
I just made a purchase of $130.00 but once I got my car and looked at the receipt, I realized the salesperson who helped me did
Andrej [43]

Answer:

Guessing you want me to figure out what your cost should have been. On it!

Step-by-step explanation:

130 * .15 = 19.5

130 - 19.5 = $110.5

That should be the new cost.

5 0
1 year ago
Which decimal is less than 0.8 and greater than 0.02<br> A.0.81<br> B.0.46<br> C.0.86<br> D.0.006
vlada-n [284]
I think it's D do you do k12

5 0
3 years ago
67000 dollars is placed in an account with an annual interest rate of 8.25%. how much will be in the account after 28 years, to
anastassius [24]

Answer:

The Amount of money in the account after 28 years is $616,674.5

Step-by-step explanation:

Given as :

The principal amount placed in the account = p = $67,000

The rate of interest = r = 8.25%

The time period of amount in the account = t = 28

Let the Amount of money in the account = $A

Now<u>, From Compound Interest method</u>

Amount = Principal × (1+\dfrac{\textrm rate}{100})^{\textrm time}

A = p × (1+\dfrac{\textrm r}{100})^{\textrm t}

Or, A = $67,000 × (1+\dfrac{\textrm 8.25}{100})^{\textrm 28}

Or, A = $67,000 × (1.0825)^{28}

Or, A = $67,000 × 9.2041

∴ A = $616,674.7

So, The Amount of money in the account = A = $616,674.5

Hence, The Amount of money in the account after 28 years is $616,674.5  Answer

5 0
2 years ago
A 2003 study of dreaming found that out of a random sample of 106 ​people, 80 reported dreaming in color.​ However, the rate of
Vlad [161]

Answer:

Step-by-step explanation:

Hello!

You have the following experiment, a random sample of 106 people was made and they were asked if they dreamed in color. 80 persons of the sample reported dreaming in color.

The historical data from the 1940s informs that the population proportion of people that dreams in color is 0.21(usually when historical data is given unless said otherwise, is considered population information)

Your study variable is a discrete variable, you can define as:

X: Amount of people that reported dreaming in colors in a sample of 106.

Binomial criteria:

1. The number of observation of the trial is fixed (In this case n = 106)

2. Each observation in the trial is independent, this means that none of the trials will have an effect on the probability of the next trial (In this case, the fact that one person dreams in color doesn't affect or modify the probability of the next one dreaming in color)

3. The probability of success in the same from one trial to another (Or success is dreaming in color and the probability is 0.21)

So X~Bi(n;ρ)

In order to be able to run a proportion Z-test you have to apply the Central Limit Theorem to approximate the distribution of the sample proportion to normal:

^ρ ≈ N(ρ; (ρ(1-ρ))/n)

With this approximation, you can use the Z-test to run the hypothesis.

Now what the investigators want to know is if the proportion of people that dreams in color has change since the 1940s, so the hypothesis is:

H₀: ρ = 0.21

H₁: ρ ≠ 0.21

α: 0.10

The test is two-tailed,

Left critical value: Z_{\alpha/2} = Z_{0.95} = -1.64

Right critical value: Z_{1-\alpha /2} = Z_{0.95} = 1.64

If the calculated Z-value ≤ -1.64 or ≥ 1.64, the decision is to reject the null hypothesis.

If -1.64 < Z-value < 1.64, then you do not reject the null hypothesis.

The sample proportion is ^ρ= x/n = 80/106 = 0.75

Z= <u>     0.75 - 0.21    </u> = 12.83

    √[(0.75*0.25)/106]

⇒Decision: Reject the null hypothesis.

p-value < 0.00001 is less than 0.10

If you were to conduct a one-tailed upper test (H₀: ρ = 0.21 vs H₁: ρ > 0.21) with the information of this sample, at the same level 10%, the critical value would be Z_{0.90}1.28 against the 12.83 from the Z-value, the decision would be to reject the null hypothesis (meaning that the proportion of people that dreams in colors has increased.)

I hope this helps!

4 0
3 years ago
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