The marks on a statistics mid-semester exam
are normally distributed with a mean of 78
and a standard deviation of 6.
a What proportion of the class has a mid-
semester mark of less than 75?
b What is the probability that a class of 50
has an average mid-semester mark that is
less than 75?
TOPIC:Normal distribution.
The marks on a statistics mid-semester exam are normally distributed with a mean of 78 and...
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...
The final exam scores in a statistics class were normally distributed with a mean of 70 and a standard deviation of five. What is the probability that a student scored more than 75% on the exam? a) 0.95 b)0.68 c) 0.16 d)0.84
Grades on the first exam in a statistics class was normally distributed with a mean of 84 and a standard deviation of 4. Your grade on this exam was a 78. What is your approximate percentile ranking on this exam? A. 6.7% B. 1.5% C.93.32% D. 98.5%
A) The distribution of exam scores for Statistics is normally distributed with a mean of 78 and a standard deviation of 5.2. What is the z-score for a raw score of 85? Round to the nearest hundredth. B) An Olympic archer is able to hit the bull’s eye 80% of the time. Assume each shot is independent of the others. She will shoot 6 arrows. Let X denote the number of bull’s eyes she makes. Find the standard deviation of...
The marks in a university statistics course are normally distributed with a mean of 68% and a standard deviation of 6%. Sketch the normal distribution for the course. Label the scale on the horizontal axis. Calculate the z-score for a student with a mark of 79%, and explain what it means. Calculate the probabilities for a student to have the following grades: (i) Greater than 60% (ii) Between 70% and 80% 2. The mid tirm grades had a...
The final exam scores in a statistics class were normally distributed with a mean of 70 and a standard deviation of 2. If you select a student at random, what is the probability that he scored between a 66 and a 74? A.2.5% B.50% C. 68% C. 95% D. none of the above
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 ?
if statistics test scores were normally distributed with a mean of 81 and a standard deviation of 4, a) what is the probability that a randomly selected student scored less than 70? b) what percentage of students had a B on the exam? c) the top 10% of the class had what grades?
Suppose that scores on a statistics exam are normally distributed with a mean of 77 and a standard deviation of 4. Find the probability of a student scoring less than 80 on the exam using the following steps. (a) What region of the normal distribution are you looking to find the area of? (to the left of a zscore, to the right of a z-score, between two z-scores, or to the left of one z-score and to the right of...
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?