Statistics and Probability Answers

Carol lives in the east end of Montreal. To get to school for her morning classes Carol has the option of taking the bus, going underground with the metro, or driving her car downtown to get to School. Carol prefers the metro, especially in the winter, and she will opt for it 50% of the time. The bus is perhaps a more convenient option since it stops near her house, so she will choose that option 40% of the time. The car is the most expensive option, but it is the most reliable, as demonstrated by the fact that she is only late for class 5% of the time when she drives. The bus is the least reliable of the options as it gets Carol to class on time 70% of the time, whereas this value increases by 10% with the metro.
d) What is the probability that Carol opted for the bus given that she was late to class?
e) What is the probability that Carol is on‐time for class given that she did not drive?

Suppose a 95 percent confidence interval for the average number of minutes a regular customer uses with a cell phone in a month is 100 plus or minus 35 minutes.

What are the lower and upper boundaries for this confidence interval?

from an urn containing balls, a ball is drawn,weighted and replaced. This experiment was repeated 5 times. The results were 5,1; 4,6; 6,2; 5,1; 4,0. The standard error of the sample mean is

Unysis.com Is one of the most frewuented business to business web sites. Assuming that the duration of a visit to this website is normally distributed with a mean of 65.7 minutes and a standard deviation of 15 minutes

Question : Less than how many minutes will only 20% of the visits last?

Carol lives in the east end of Montreal. To get to school for her morning classes Carol has the option of taking the bus, going underground with the metro, or driving her car downtown to get to School. Carol prefers the metro, especially in the winter, and she will opt for it 50% of the time. The bus is perhaps a more convenient option since it stops near her house, so she will choose that option 40% of the time. The car is the most expensive option, but it is the most reliable, as demonstrated by the fact that she is only late for class 5% of the time when she drives. The bus is the least reliable of the options as it gets Carol to class on time 70% of the time, whereas this value increases by 10% with the metro.
a) What is the probability that Carol is late to class on a given morning?
b) What is the probability that Carol took the metro and is on time for class?
c) What is the probability that Carol did not drive and is on time for class?
d) What is the probability that Carol opted for the bus given tha

The batteries to the remote control for your television have just run out. You find your collection of
miscellaneous “AA” batteries and grab 2 of them to replace the used ones. The box you used to fish out the replacements contained 14 batteries, but you were unaware that 3 of them were faulty and did not work.
a) If the remote control requires two good batteries to operate properly, what is the probability
that the remote control now works properly?
b) Given that the remote control is now working, what is the probability that the next two
batteries you select from your remaining stash will also work?

The I . Q . of students of a school was found to be normally distributed with a mean µ = 116 and a standard deviation of σ = 8 . What % age of children have I . Q . from 100 to 124 .

A group of 5 boys and 4 girls are to be photographed. In how many ways can they be arranged such that:

(i) No two girls sit together?

(ii) No two boys sit together?

In a group of 15 boys, there are 6 scouts. In how many ways can 8 boys be selected, so as to include

(i) exactly 3 scouts

(ii) at least 3 scouts

(iii) at the most 3 scouts

There are 7 English, 5 Marathi and 4 Hindi Books. In how many ways can they be arranged in a shelf such that,

(i) the books are language wise.

(ii) the books are not language wise strictly, although some but not all books of same language may be together.