8x² - 4 = 28
8x² = 28 + 4
8x² = 32
x² = 32/8
x² = 4
x = <span>±2
</span>
Answer:
The value of the test statistic is 
Step-by-step explanation:
The null hypothesis is:

The alternate hypotesis is:

Our test statistic is:

In which X is the sample mean,
is the value tested at the null hypothesis,
is the standard deviation and n is the size of the sample.
In this problem, we have that:

Then



The value of the test statistic is 
Answer:

Step-by-step explanation:
We have the cone and the half-sphere.
The formula of a volume of a cone:

r - radius
H - height
We have r = 7cm and H = (22-7)cm=15cm. Substitute:

The formula of a volume of a sphere:

R - radius
Therefore the formula of a volume of a half-sphere:

We have R = 7cm. Substitute:

The volume of the given shape:

Substitute:
