need help...please

#1
Greetings,

I'm studying stats independently online from my university so don't have a teacher to ask how to finish these question. Any help would be much appreciated. Because I dnt know what im doing wrong and I just cant figure it out. thank you.


Problems:

A probability distribution has two requirements:
1)
2)

a)Is this a probability distribution? why or why not?

x|p(x)
------
0|0.2
1|0.5
2|0.4
3|0.3

b) does p(x)= x/3 (x=0,1,2) determine a probability distribution?



customer waiting time in bank lines:

a (single line) 6.5, 6.6, 6.7, 6.8, 7.1, 7.3, 7.4, 7.7, 7.7, 7.7
b(individual lines) 4.2, 5.4, 5.8, 6.2, 6.7, 7.7, 7.7 ,8.5 , 9.3 , 10.0

a)find the mean, median, mude, variance, standard deviation and rang of each data set. which set appears to be the fastest?


b)perform a hypothesis test to see if one method appears to be more efficient that other. hint:(test 2 means). show the null and alternative hypotheses, the critical valve at alpha= 0.05, the test statistic, and the p-value. lastly, show (explain) your conclusion.
 
#2
What is the probability that it will rain sometime in the next 50 years?
What is the probability that it will not rain sometime in the next 50 years?

There is your answer to all but the bank problem

Peter