Use the confidence interval to find the estimated margin of error. Then find the sample mean. A biologist reports a confidence interval of (3.0 comma 4.0 )when estimating the mean height (in centimeters) of a sample of seedlings.

3.5

Step-by-step explanation:

The confidence interval is defined by the following equation:

I = m +/- E

In other words, it is equal to the mean plus or minus the error.

Now, to calculate error it is necessary to divide the width of the confidence interval by 2. The values we have are 3 and 4. Therefore:

E = (4 - 3) / 2 = 1/2

E = 0.5

It means that error is 0.5

To calculate the mean, you must add the margin of error to the left end point or subtract the margin of error from the right end point.

We will do both cases, it must give the same:

4 - 0.5 = 3.5

3 + 0.5 = 3.5

Therefore, the mean is equal to 3.5.

it's equivalent, so we can say that its equal.

let's call the denominator x and the numerador is 18 less then denominator, x - 18.

multiply

2.x = 5.(x - 18)

2x = 5x - 90

90 = 5x - 2x

90 = 3x

x = 90/3

x = 30

so: