Here, μ = 72, σ = 8, x1 = 60 and x2 = 84. We need to compute P(60<= X <= 84). The corresponding z-value is calculated using Central Limit Theorem
z = (x - μ)/σ
z1 = (60 - 72)/8 = -1.5
z2 = (84 - 72)/8 = 1.5
Therefore, we get
P(60 <= X <= 84) = P((84 - 72)/8) <= z <= (84 -
72)/8)
= P(-1.5 <= z <= 1.5) = P(z <= 1.5) - P(z <=
-1.5)
= 0.9332 - 0.0668
= 0.8664
Option C
The final exam scores of students taking a statistics course are normally distributed with a population...
Scores on a recent national statistics exam were normally distributed with a mean of 72 and a standard deviation of 10 . What is the probability that a randomly selected exam will have a score between 75 and 80 ?
Juan took a Statistics exam and earned a 90%. If the exam scores are normally distributed with a mean = 75% and SD = 10%, what is Juan's z score? Based on his z score, what percentage of students scored below Juan? What is the probability of randomly selecting a student who scored below Juan?
A professor of statistics noticed that the marks in his course are normally distributed. He also noticed that his morning classes average 75% with a standard deviation of 13% on their final exams. His afternoon classes average 76% with a standard deviation of 12%. A. What is the probability that a randomly selected student in the morning class has a higher final exam mark than a randomly selected student from an afternoon class? Probability = .4761 B. What is the...
On a certain statistics exam, the time for students to submit the exam is normally distributed with a mean of 0.9 hours and a standard deviation of 0.1 hours. What is the probability that a randomly selected student will take longer than an hour and a half to submit the exam? O 0.707 1 0.5 0.0000000001 Page 14 Previous Page Next Page
On a certain statistics exam, the time for students to submit the exam is normally distributed with a mean of 0.9 hours and a standard deviation of 0.1 hours. What is the probability that a randomly selected student will take longer than an hour and a half to submit the exam? O 0.707 O1 0.5 0.0000000001 Page 14 Previous Page Next Page
Exam grades: Scores on a statistics final in a large class were normally distributed with a mean of 79 and a standard deviation of 8. Use the TI-84 PLUS calculator to answer the following. Round the answers to at least four decimal places. (a) What proportion of the scores were above 932 (b) What proportion of the scores were below 66? (c) What is the probability that a randomly chosen score is between 70 and 90? Part: 0/3 Part 1...
Exam grades: Scores on a statistics final in a large class were normally distributed with a mean of 70 and a standard deviation of 11. Use the TI-84 PLUS calculator to answer the following. Round the answers to at least four decimal places. (a) What proportion of the scores were above 85? (b) What proportion of the scores were below 55? (c) What is the probability that a randomly chosen score is between 60 and 80? Part: 0/3 Part 1...
Exam grades: Scores on a statistics final in a large class were normally distributed with a mean of 79 and a standard deviation of 8. Use the TI-84 PLUS calculator to answer the following. Round the answers to at least four decimal places. (a) What proportion of the scores were above 93? (b) What proportion of the scores were below 66? (c) What is the probability that a randomly chosen score is between 70 and 90?
Student scores on Professor Combs' Stats final exam are normally distributed with a mean of 72 and a standard deviation of 7.2 Find the probability of the following: (use 4 decimal places) a) The probability that one student chosen at random scores above an 77 b) The probability that 10 students chosen at random have a mean score above an 77 c) The probability that one student chosen at random scores between a 67 and an 77 d) The probability...
A set of final examinations grades in an introductory statistics course is normally distributed, with a mean of 75 and a standard deviation of 7. Complete parts (a) through (d). a.) What is the probability that a student scored below 87 on this exam? b.) What is the probability that a student scored between 68 and 90? c.) The probability is 25% that a student taking the test scores higher than what grade? d.) If the professor grades on a...