Competency Apply the normal distribution, standar

Instructions – Read First

Instructions: The following questions on the next six tabs are shown to you by a student who is asking for help. Your job is to help the student walk through the problems by showing the student how to solve each problem in detail. You are expected to explain all of the steps in your own words. Key: <i> – This problem is an incorrect. Your job is to find the errors, correct the errors, and explain what they did wrong. <p> – This problem is partially finished. You must complete the problem by showing all steps and explain your corrections. <b> – This problem is blank. You must start from scratch and explain how you will approach the problem, how you solve it, and explain why you took each step.

Question 1

<b> Assume that a randomly selected subject is given a bone density test. Those tests follow a standard normal distribution. Find the probability that the bone density score for this subject is between -0.87 and 1.98.   Show your calculations using Excel functions in the area to the right of this text box and answer the problem with explanations below.

Question 2

<b> The U.S. Airforce requires that pilots have a height between 64 in. and 72 in. If women’s heights are normally distributed with a mean of 63.7 in. and a standard deviation of 2.5 in, find the percentage of women that meet the height requirement. Show your calculations using Excel functions in the area to the right of this text box and answer the problem with explanations below.

Question 3

Question 4

<p> What is the cumulative area from the left under the curve for a z-score of -0.55? What is the area on the right of that z-score? Hint: You will have two answers (one for the left and one for the right). Student’s partially finished answer: The first part is to find the cumulative area from the left under the curve for a z-score of -0.55. This means that I need to find the probability that a z-score is less than -0.55. Show your calculations using Excel functions in the area to the right of this text box and finish answering the problem with explanations below.

Question 5

<i> If the area under the standard normal distribution curve is 0.0968 from the right, what is the corresponding z-score?   Student’s incorrect answer: We plug in “=NORM.S.INV(0.0968)” into Excel and get a z-score of -1.3. Identify where the student went wrong when solving the problem above. Show how to correctly calculate the answer using Excel in the area to the right of this text box. Finish the problem by stating how to correctly set up the problem and solve it below.

Question 6

<p> A research shows that the Richter scale magnitudes of earthquakes are normally distributed with a mean of 1.385 and a standard deviation of 0.715. Earthquakes with magnitudes less than 2.00 are considered "microearthquakes" that humans do not feel. What percentage of earthquakes fall into this category?   Student’s partially finished answer: We need to find the probability that earthquakes fall into the microearthquake category. The first step is to find the probability that the Richter scale is less than 2.00. Show your calculations using Excel functions in the area to the right of this text box and finish answering the problem with explanations below.