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____ [38]
3 years ago
5

Suppose that the ages of cars driven by employees at a company are normally distributed with a mean of 8 years and a standard de

viation of 3.2 years.
What is the z-score of a car that is 9.1 years old?
Mathematics
2 answers:
choli [55]3 years ago
6 0

There follows the formula for "z-score:"

raw score - mean

z = ------------------------------

standard dev

9.1 - 8

Here, the z-score is z = ------------- = 0.344

3.2

11111nata11111 [884]3 years ago
6 0

Answer: The z-score of a car is 0.34375.

Step-by-step explanation:

Since we have given that

The ages of cars driven by employees at a company are normally distributed.

Mean = \mu = 8 years

Standard deviation = \sigma = 3.2 years

Age of car = X = 9.1 years old.

We  need to find the z-score of a car which is given by

z=\frac{X-\mu}\sigma}\\\\z=\frac{9.1-8}{3.2}\\\\z=\frac{1.1}{3.2}\\\\z=0.34375

Hence, the z-score of a car is 0.34375.

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$2.00 is the answer...
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There are big spenders among University of Alabama football season ticket holders. This data set Roll Tide!! shows the dollar am
Bas_tet [7]

Using the z-distribution, as we have a proportion, the 95% confidence interval is (0.2316, 0.3112).

<h3>What is a confidence interval of proportions?</h3>

A confidence interval of proportions is given by:

\pi \pm z\sqrt{\frac{\pi(1-\pi)}{n}}

In which:

  • \pi is the sample proportion.
  • z is the critical value.
  • n is the sample size.

In this problem, we have a 95% confidence level, hence\alpha = 0.95, z is the value of Z that has a p-value of \frac{1+0.95}{2} = 0.975, so the critical value is z = 1.96.

We also consider that 130 out of the 479 season ticket holders spent $1000 or more at the previous two home football games, hence:

n = 479, \pi = \frac{130}{479} = 0.2714

Hence the bounds of the interval are found as follows:

\pi - z\sqrt{\frac{\pi(1-\pi)}{n}} = 0.2714 - 1.96\sqrt{\frac{0.2714(0.7286)}{479}} = 0.2316

\pi + z\sqrt{\frac{\pi(1-\pi)}{n}} = 0.2714 + 1.96\sqrt{\frac{0.2714(0.7286)}{479}} = 0.3112

The 95% confidence interval is (0.2316, 0.3112).

More can be learned about the z-distribution at brainly.com/question/25890103

7 0
2 years ago
The car travels an average of 40km per litre of fuel, and the cost of fuel is £1.25 per litre. Calculate the cost of the fuel fo
Nuetrik [128]

31075  \div 40 = 776.875 \\ 776.875 \times 1.25 = 971.09375
The cost of fuel was £971.09
5 0
3 years ago
Help plss
svlad2 [7]

Answer:

????

Step-by-step explanation:

4 0
3 years ago
Read 2 more answers
−2x=x2−6 Rewrite the equation by completing the square.
V125BC [204]

Answer:

(x + 1)² = 7

Step-by-step explanation:

Given:

-2x = x² - 6

We'll start by rearranging it to solve for zero:

x² + 2x - 6 = 0

The first term is already a perfect square so that's fine.  Normally, if that term had a non-square coefficient, you would need to multiply all terms a value that would change that constant to a perfect square.

Because it's already square (1), we can simply move to the next step, separating the -6 into a value that can be doubled to give us the 2, the coefficient of the second term.  That value will of course be 1, giving us:

x² + 2x + 1 - 1 - 6 = 0

Now can group our perfect square on the left and our constants on the right:

x² + 2x + 1 - 7= 0

x² + 2x + 1 = 7

(x + 1)² = 7

To check our answer, we can solve for x:

x + 1 = ± √7

x = -1 ± √7

x ≈ 1.65, -3.65

Let's try one of those in the original equation:

-2x = x² - 6

-2(1.65) = 1.65² - 6

- 3.3 = 2.72 - 6

-3.3 = -3.28

Good.  Given our rounding that difference of 2/100 is acceptable, so the answer is correct.

6 0
3 years ago
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