Question

The amount of time it takes for a student to complete a statistics exam is given by a random variable that is uniformly distributed between 28 and 61 minutes. A student is selected at random. Find the probability of the following events. In each case, give exact answers or round to at least three decimal places.

1. The student’s time was between 34 and 39 minutes
2. The student’s time was less than 34 minutes
3. The student’s time was between 39 and 72 minutes
4. The student’s time was more than 34 minutes
5. The student’s time was between 22 and 34 minutes

IQ scores among recent college graduates have a mean of 101.7 and standard deviation of 13.3.

1. A recent college graduate with an IQ score of 135 has a standardized score of
2. A recent college graduate with an IQ score of 63 has a standardized score of
3. A standardized IQ score of z = 1.87 corresponds to an actual IQ score of
4. A standardized IQ score of z = -2.49 corresponds to an actual IQ score of

A large set of scores on the Math SAT in a certain year had an approximately Normal distribution with a mean of 513 and standard deviation of 78.

(a) Fill in the blank:   percent of scores were less than 374.

(b) Fill in the blank: percent of scores were greater than 647.

(c) Fill in the blank:    percent of scores were between 374 and 647.

In each case, give your answers in percentage form and round to at least two decimal places.

Answer 1