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:
positive 15
Step-by-step explanation:
opposite of negative is positive
Answer: 19/100
explanation: it has a 19% chance so it is 19/100
The range is the high and low points.
So (5, 2]
90% x 18 = 16.2
Therefore, you answered about 16 questions correctly out of 18.