Question

The time, in minutes spent texting in class, is approximately normally distributed with a mean of 6.2 minutes and a standard of 1.6 minutes.

The distance, in city blocks, that a student must travel to get from one class to the next has a Chi-squared distribution with 4 degrees of freedom. (The standard city block is approximately 400 feet long)

1) What is the probability that the average time spent texting in a class of 12 random students is between 4 and 7 minutes?

2) What is the probability that the standard deviation in the time spent texting in class of 12 random students is between 4 and 7 minutes?

3) If 140 students are randomly selected, what is the probability that less than 25 of them must travel more than 7 blocks to get from one class to the next.

4) If 140 students are randomly selected, what is the probability that the average distance that a student must travel to get from one class to the next is more than 7 blocks?

5) If 140 students are randomly selected, what is the probability that the standard deviation in the number of blocks that a student must travel to get from one class to the next is less than 5 blocks?

- Graph all and include calculator function.

Answer 1