Self-Quiz Unit 6 Answers Introduction to Statistics (MATH 1280 )

Information Flag question Informationtext According to some study, the height for Northern European adult males is normally distributed with an average of 181 centimeter and a standard deviation of 7.3 centimeter. Suppose such an adult male is randomly chosen. Let X be height of that person. The next 3 questions correspond to this information. The answer may be rounded up to 3 decimal places of the actual value. Question 1 Correct Mark 1.00 out of 1.00 Flag question Question text The probability that the person is between 160 and 170 centimeters is Answer: Feedback The distribution of X is Normal(181,(7.3)2). The Probability of the interval is equal to the difference between P(X ≤ 170) and P(X ≤ 160) > pnorm(170,181,7.3) - pnorm(160,181,7.3) [1] 0.06391543 Question 2 Correct Mark 1.00 out of 1.00 Flag question Question text The probability that the person is higher than 190 centimeter is Answer: Feedback The distribution of X is Normal(181,(7.3)2). The Probability of being larger than 190 is equal to the difference between 1 and P(X ≤ 190) > 1 - pnorm(190,181,7.3) [1] 0.1088109 Question 3 Correct Mark 1.00 out of 1.00 Flag question Question text The middle 60% of heights fall between what two values? Select one: a. (171.6, 190.4) b. (173.4, 188.6) c. (174.9, 187.1) d. (176.1, 185.7) Feedback The distribution of X is Normal(181,(7.3)2). The central region that contains 60% of the distribution is the region between the 0.2-percentile and the 0.8-percentile > qnorm(0.2,181,7.3) [1] 174.8562 > qnorm(0.8,181,7.3) [1] 187.1438 Information Flag question Information text Terri Vogel, an amateur motorcycle racer, averages 129.71 seconds per 2.5 mile lap (in a 7 lap race) with a standard deviation of 2.28 seconds . The distribution of her race times is normally distributed. We are interested in one of her randomly selected laps. The next 4 questions correspond to this information. The answer may be rounded up to 3 decimal places of the actual value: