Using the numbers 8,6,4, and 2 write and expression that equals 20

Any help greatly appreciated

REY [17]

Answer:

Option B. 8.6%

Step-by-step explanation:

Simple index of two stocks: i=?

i=[(5,000*5.1+2,500*7.45)/(5,000*4.5+2,500*7.25)-1]*100%

i=[(25,500+18,625)/(22,500+18,125)-1]*100%

i=[(44,125)/(40,625)-1]*100%

i=[1.086153846-1]*100%

i=[0.086153846]*100%

i=8.6153846%

i=8.6%

8 0

2 years ago

Researchers at the National Cancer Institute released the results of a study that investigated the effect of weed-killing herbic

jolli1 [7]

Answer:

The 95% confidence interval for the difference in the proportion of cancer diagnoses between the two groups is (0.3834, 0.5166).

Step-by-step explanation:

Before building the confidence interval, we need to understand the central limit theorem and subtraction between normal variables.

Central Limit Theorem

The Central Limit Theorem estabilishes that, for a normally distributed random variable X, with mean $\mu$ and standard deviation $\sigma$ , the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean $\mu$ and standard deviation $s = \frac{\sigma}{\sqrt{n}}$ .

For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.

For a proportion p in a sample of size n, the sampling distribution of the sample proportion will be approximately normal with mean $\mu = p$ and standard deviation $s = \sqrt{\frac{p(1-p)}{n}}$

Subtraction between normal variables:

When two normal variables are subtracted, the mean is the difference of the means, while the standard deviation is the square root of the sum of the variances.

The randomly sampled 400 dogs from homes where an herbicide was used on a regular basis, diagnosing lymphoma in 230 of them.

This means that:

$p_h = \frac{230}{400} = 0.575, s_h = \sqrt{\frac{0.575*0.425}{400}} = 0.0247$

Of 200 dogs randomly sampled from homes where no herbicides were used, only 25 were found to have lymphoma.

This means that:

$p_n = \frac{25}{200} = 0.125, s_n = \sqrt{\frac{0.125*0.875}{200}} = 0.0234$

Distribution of the difference:

$p = p_h - p_n = 0.575 - 0.125 = 0.45$

$s = \sqrt{s_h^2+s_n^2} = \sqrt{0.0247^2 + 0.0234^2} = 0.034$

Confidence interval:

The confidence interval is:

$p \pm zs$

In which

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

95% confidence level

So $\alpha = 0.05$ , z is the value of Z that has a pvalue of $1 - \frac{0.05}{2} = 0.975$ , so $Z = 1.96$ .

The lower bound is $0.45 - 1.96(0.034) = 0.3834$

The upper bound is $0.45 + 1.96(0.034) = 0.5166$

The 95% confidence interval for the difference in the proportion of cancer diagnoses between the two groups is (0.3834, 0.5166).

3 0

3 years ago

Will mark brainliest+ 10 points

olga2289 [7]

The answer without a doubt is 69/420

3 0

2 years ago

An aquarium has a base area of 6 square feet and a height of 2 feet. Will the aquarium fit in 15 cubic feet of space? Explain wh

Brums [2.3K]

Answer:

Yes, the aquarium will fit in 15 cubic feet of space.

Step-by-step explanation:

Given:

An aquarium has a base area of 6 square feet and a height of 2 feet.

Now, to find will the aquarium fit in 15 cubic feet of space or not.

So, as given the dimensions:

Base area = 6 square feet.

Height = 2 feet.

Now, to get the volume of aquarium by using formula:

$Volume=base\ area\times height\\\\Volume=6\times 2\\\\Volume=12\ cubic\ feet.$

As, the volume of aquarium is 12 cubic feet.

And, the aquarium to be fit in 15 cubic feet space. So, 15 is more than 12.

Thus, the aquarium will be fit in 15 cubic feet space.

Therefore, the aquarium will fit in 15 cubic feet of space.

7 0

2 years ago

1 hat cost $12

Ivan

Answer:

he bought 6 hats.

Step-by-step explanation:

im just gonna go through this 1 at a time. starting at 1.

12 + (14x9) = 138

(12x5)+(14x5) = 130

(12x4)+(14x6) = 132

(12x8)+(14x2) = 124

(12x6)+(14x4) = 128

6 0

2 years ago