During the las week of the semester, students at a certain college spend on the average 4.5 hours using the

1. During the las week of the semester, students at a certain college spend on the average 4.5 hours using the school's computer terminals with a standard deviation of 1.8 hours. For a random sample of 36 stduents at the college, find the probabilities that the average time spend using the computer terminal during the last week of the semester is

a. at least 4.8 hours

b. between 4.1 and 4.5 hours.

2. Ten randomly selected shut-ins were each asked to list how many hours of television they watched per week. The results were:

2 66 100 84 75 88 82 94 110 91

a. Find x-bar 

b. Find s

c. How many degrees of freedom will you use?

Hint df = (n-1) when computing s

3. A cab driver knows from experience that the number of fares he will pick up in an evening is a random variable with u = 21 and standard deviation = 3.4. Assuming that the distribution of this random variable can be approximated closely with a normal curve, find the probabilities that in an evening the driver will pick up (a) at least 30 fares (b) anywhere from 20 to 25 fares (including 20 and 25). Since the number of fares is a dicrete random variable, and we are using a normal curve, we will need continuity correction on both parts a and b above. These continuity correction are given below.

a. P(At least 30 fares) = P(X greater than or equal to 30) = P(X>29.5) after continuity correction. If you don't know what a contiunity correction is, Please find this probability for the given normal distribution: P(X>29.5).

b. P(between 20 and 25 fares inclusive) = P(19.5<X<25.5) after a continuity correction. Please find this probability.

Please see attached question...