Answer:
The 80% confidence interval for the the population mean nitrate concentration is (0.144, 0.186).
Critical value t=1.318
Step-by-step explanation:
We have to calculate a 80% confidence interval for the mean.
The population standard deviation is not known, so we have to estimate it from the sample standard deviation and use a t-students distribution to calculate the critical value.
The sample mean is M=0.165.
The sample size is N=25.
When σ is not known, s divided by the square root of N is used as an estimate of σM:

The degrees of freedom for this sample size are:

The t-value for a 80% confidence interval and 24 degrees of freedom is t=1.318.
The margin of error (MOE) can be calculated as:
Then, the lower and upper bounds of the confidence interval are:

The 80% confidence interval for the population mean nitrate concentration is (0.144, 0.186).
If they don't have water they can die because they breathe water.
Answer:
<em>15.4 </em>
Step-by-step explanation:
= tan51.3° ⇒ u = 4tan51.3° ≈ 5
= cos51.3° ⇒ v =
≈ 6.4
<em>P </em>≈ 4 + 5 + 6.4 = <em>15.4</em>
Solve the equation.
m+34=m−6
Enter the correct answer in the box.