1. The lengths of time bank customers must wait for a teller are normally distributed, with a mean of 2.5 minutes and a standard deviation of 1 minute.
- What proportion of bank customers waits between 3 and 4.25 minutes
- What percentage wait more than 4 minutes?
- What proportion waits between 1 and 3.25 minutes?
- What percentage wait less than 1 minute?
2. To estimate the medical charges for an appendectomy Blue Star Insurance has data from a random sample of 60 patients. The sample mean cost is $420, with a sample standard deviation of $80. Construct a 95% confidence interval for the population mean cost.
We are 95% confident that the populations mean costs of patients' medical charges for an appendectomy through Blue Star Insurance range is between _____________ and ________________
3.
|
|
Democrat
|
Republican
|
Independent
|
|
DC
|
10
|
15
|
65
|
|
Chicago
|
35
|
25
|
75
|
|
North Carolina
|
60
|
20
|
70
|
A group of voters from 3 states were selected and the results are above.
What is the probability of selecting a random voter from Chicago, given that the voter was a republican?
a).357
b).417
c).267
d).200
4.
|
|
Republican
|
Democratic
|
Independent
|
|
Maryland
|
10
|
15
|
65
|
|
Los Angeles
|
35
|
25
|
75
|
|
Detroit
|
60
|
20
|
70
|
A group of voters from 3 areas were selected and the results are above.
What is the probability of selecting a random voter that is from Detroit or a Republican?
a).093
b).520
c).613
d).357
5. There is a bag with 62 balls. 31 are yellow and 31 are red. In 20 pulls from the bag, 20 balls are red. What is the probability with replacement that the 21st pull will be red?
a) .5000
b) .2500
c) .000000477
d) .03125
e) None of the above