Answer the following questions from our classes probability and z-scores. Round

Question

Answer the following questions from our classes probability and z-scores. Round all answers to the hundredths place (2 places past the decimal). Also for this exercise, make sure that you do not include the + symbol for positive z-scores or % for percentages. (These are silly iCollege rules. Sorry for the inconvenience.) Make sure to read each question carefully. The wording and the numbers will change each time you take it. You will be graded for accuracy and will receive the highest grade you obtain before 5:30 on Monday October 12. No attempts past the deadline will count towards your grade, but the exercise will still be available to you so that you can use it to practice for the test.  

Question a

Tonya gives a personality assessment to her classmates. The assessment rates levels of extroversion on a scale of 1 (very introverted) to 5 (very extroverted). 7 students receive a 1, 8 students receive a 2, 9 students receive a 3, 5 students receive a 4, and 5 students receive a 5. If she were pick one student out of the group at random, what is the probability that that student would have received an extroversion score that is less than 2? (Write your answer as a proportion rounded to two decimal places.)

Your Answer:Question 1 options:

Question b (2 points)

For the entire population of MMA fighters, the mean speed is 23 with a standard deviation of 4.92. If a fighter has a speed score of 60, what will his z-score equal? (Do not include a + symbol for positive z-scores for this exercise.)

Your Answer:Question 2 options:

Question c (2 points)

What percent of scores would fall below a z-score of -1.25?

Question d (2 points)

45% of all scores will fall below what z-score?

Question e (2 points)

What proportion of scores would fall between a z-score of -1.25 and -2.50?

Explanation / Answer

A) P(X < 2) = P(x = 1) = 7/34 = 0.21

B) Z-score = (60 - 23)/4.92 = 7.52

C) P(Z < -1.25) = 0.1056 = 10.56

D) P(Z < z) = 0.45

Z = -0.12

E) P(-2.50 < Z < -1.25) = P(-1.25) - P(-2.50)

= 0.1056 - 0.0062 = 0.0994

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