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3 years ago

Evaluate the expression for r = 14.

Mathematics

1 answer:

pogonyaev3 years ago

3 0

Answer:

Need more information, r=14 there isnt an equation

Step-by-step explanation:

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According to a recent publication, the mean price of new mobile homes is $63 comma 800. Assume a standard deviation of $7900.

wolverine [178]

Answer:

a. For n=25, the mean and standard deviation of the prices of the mobile homes all possible sample mean prices are $63,800 and $1,580, respectively.

b. For n=50, the mean and standard deviation of the prices of the mobile homes all possible sample mean prices are $63,800 and $1,117, respectively.

Step-by-step explanation:

In this case, for each sample size, we have a sampling distribution (a distribution for the population of sample means), with the following parameters:

$\mu_s=\mu=63,800\\\\\sigma_s=\sigma/\sqrt{n}=7,900/\sqrt{n}$

For n=25 we have:

$\mu_s=\mu=63,800\\\\\sigma_s=\sigma/\sqrt{n}=7,900/\sqrt{25}=7,900/5=1,580$

The spread of the sampling distribution is always smaller than the population spread of the individuals. The spread is smaller as the sample size increase.

This has the implication that is expected to have more precision in the estimation of the population mean when we use bigger samples than smaller ones.

If n=50, we have:

$\mu_s=\mu=63,800\\\\\sigma_s=\sigma/\sqrt{n}=7,900/\sqrt{50}=7,900/7.07=1,117$

4 0

4 years ago

Solve the system x-z=5, 2x+y= 7, y+3z=12

Wewaii [24]

x,z,y = 20,15,-33

i think thats it im sorry

7 0

3 years ago

Gerald has a bag of 10 colored balls: 3 green, 3 red, and the rest yellow. He randomly draws two balls, one at a time without re

butalik [34]

Answer:

2/3

Step-by-step explanation:

Probability is the ratio of the number of possible outcome to the number of total outcome.

Given that there are 10 balls of which 3 green, 3 red, and the rest yellow

Number of yellow balls = 10 - 3 - 3 = 4

Probability of picking a;

Green ball = 3/10

Red ball = 3/10

Yellow ball = 4/10

If two balls are picked without replacement, the probability that one is at least yellow will be

YR RY YG GY YY

= 4/10*3/9 + 3/10*4/9 + 4/10*3/9 + 3/10*4/9 + 4/10*3/9

=12/90 *5

= 2/3

3 0

3 years ago

A survey of 542 consumers reveals that 301 favor the new design for a product. Construct a 90% confidence interval for the true

kodGreya [7K]

Answer:

The 90% confidence interval for the true proportion of all consumers who favor the design is (0.52, 0.59).

Step-by-step explanation:

In a sample with a number n of people surveyed with a probability of a success of $\pi$ , and a confidence level of $1-\alpha$ , we have the following confidence interval of proportions.

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

In which

z is the zscore that has a pvalue of $1 - \frac{\alpha}{2}$ .

For this problem, we have that:

$n = 542, \pi = \frac{301}{542} = 0.555$

90% confidence level

So $\alpha = 0.1$ , z is the value of Z that has a pvalue of $1 - \frac{0.1}{2} = 0.95$ , so $Z = 1.645$ .

The lower limit of this interval is:

$\pi - z\sqrt{\frac{\pi(1-\pi)}{n}} = 0.555 - 1.645\sqrt{\frac{0.555*0.445}{542}} = 0.52$

The upper limit of this interval is:

$\pi + z\sqrt{\frac{\pi(1-\pi)}{n}} = 0.555 + 1.645\sqrt{\frac{0.555*0.445}{542}} = 0.59$

The 90% confidence interval for the true proportion of all consumers who favor the design is (0.52, 0.59).

5 0

3 years ago

Erode is 4/7 of a mile long a crew needs to repave 3/7 of it how long is the section that needs to be repaved in simplest form

Citrus2011 [14]

12/49

4*3=12
7*7=49
12/49 miles long is being repaved.

This can be tested by taking a mile (in feet for example) and multiplying 5280 ft by 4/7 then by 3/7 to get the same answer as taking 5280 ft times 12/49.

8 0

3 years ago