Answer:
Hi!
Your answer is:
25d
Since we aren't aware of how many days he is working, we substitute a variable (d) in for it!
I hope this helps!
Answer:
a) P(2)=0.270
b) P(X>3)=0.605
c) P=0.410
Step-by-step explanation:
We know that customers arrive at a grocery store at an average of 2.1 per minute. We use the Poisson distribution:

a) In this case: 

Therefore, the probability is P(2)=0.270.
b) In this case: 

Therefore, the probability is P(X>3)=0.605.
c) We know that two customers came in in the first minute. That is why we calculate the probability of at least 5 customers entering the other 2 minutes.
In this case: 

Therefore, the probability is P=0.410.
Answer:
its 2
Step-by-step explanation:
because 2*2*2 is 8
She asked her friends, which does not represent a random sample.
She tried to show cause and effect without doing an experiment (which includes simple random sample, control group, treatment, etc).
So the answer is she did not use a random sample, and tried to show cause and effect with an observational study.