statistic assignment

DS301 Fall2018 HW7 Page 1

DS 301.01 Fall 2018 Homework 7 Q1. The waiting time of the traffic signal at the intersection of Hubbard and Evergreen is equally likely at a range from zero to five minutes.

1. Calculate the expected waiting time at the signal

2. What is the probability that you pass the signal in less than 1 and half minutes?

3. What is the probability that you get stuck there for more than two minutes?

UMID: ________________________

Name: _________________________

DS301 Fall2018 HW7 Page 2

Q2. Find the following z values for the standard normal variable Z

1. 𝑃𝑃(𝑍𝑍 ≤ 𝑧𝑧) = 0.9744

2. 𝑃𝑃(𝑍𝑍 > 𝑧𝑧) = 0.8389

3. 𝑃𝑃(−𝑧𝑧 ≤ 𝑍𝑍 ≤ 𝑧𝑧) = 0.95

4. 𝑃𝑃(−0 ≤ 𝑍𝑍 ≤ 𝑧𝑧) = 0.3315

DS301 Fall2018 HW7 Page 3

Q3. Students at the University of Michigan-Dearborn take an average of 11 phone calls per day. Assume the number of calls is normally distributed with a standard deviation of 4.

1. What is the probability that an average UMD student takes between 3 and 17 calls per day?

2. What is probability that an average UMD student take more than 7 calls per day?

3. What is the probability that an average UMD student take more than 19 calls per day?