Answer:
Abc is the whole explanation.
Answer: A
Please mark brainliest!
Answer: 

Step-by-step explanation:
- A null hypothesis is a hypothesis where a researcher generally try to disprove, it says that there is no statistically significant relationship between the two variables .
- An alternative hypothesis says that there is a statistical significance between two variables.
Claim 1. : Mean age of online dating service users is 40 years.
i.e.
, since it has equals sign so we take this as null hypothesis.
Claim 2. : Mean age of online dating service users is not 40 years.
⇒ Null Hypothesis : 
Alternative hypothesis : 
Answer: The area is approximately 314 ft^2
Step-by-step explanation:
Well if the diameter is 20 feet then the radius will be 10 because the radius is half the diameter, and to find the area of a circle, you use the formula
A=
where A is the area and pi times the radius squared.
We will represent pi by 3.14
A= 3.14* 10^2
A= 3.14 * 100
A = 314