Students who take statistics courses have a normal distribution period of 55 minutes on average and 15 minutes of standard deviation. Find the probability that any student spends 65-85 minutes on the exam.
Solution-
According to question, students who take statistics courses have a normal distribution period of 55 minutes on average and 15 minutes of standard deviation.
So, mean =
= 55 minutes
And Standard deviation =
= 15 minutes.
If the random normal variable is X.Then
The probability that any student spends 65-85 minutes
= P( 65 < X < 85)
= 0.4772 - 0.2486
= 0.2286
(Values are taken from standard normal distribution table).
Hence, Probability that any student spends 65 minutes to 85 minutes is 0.2286 .
Students who take statistics courses have a normal distribution period of 55 minutes on average and...
Each year about 1500 students take the introductory statistics course at a large university. This year scores on the nal exam are distributed with a median of 74 points, a mean of 70 points, and a standard deviation of 10 points. There are no students who scored above 100 (the maximum score attainable on the nal) but a few students scored below 20 points. (a) Is the distribution of scores on this nal exam symmetric, right skewed, or left skewed?...
A statistics instructor collected data on the time it takes the students to complete a test. The test taking time is uniformly distributed within a range of 55 minutes to 85 minutes. a) Determine the height and draw this uniform distribution. b) How long is the typical test taking time? c) Determine the standard deviation of the test taking time. d) What is the probability a particular student will take less than 60 minutes? e) What is the probability a...
The average time taken to complete an exam, X, follows a normal probability distribution with mean = 60 minutes and standard deviation 30 minutes. What is the probability that a randomly chosen student will take more than 45 minutes to complete the exam?
The time required for a student to complete a Statistics exam is normally distributed with a mean of 55 minutes and a standard deviation of 12 minutes. What percent of students take between 40 and 50 minutes to complete an exam? At what point in time will 25 percent of the students have completed the exam?
The length of time it takes college students to find a parking spot in the library parking lot follows anormal distribution with a mean of 5.5 minutes and a standard deviation of 1 minute. Find theprobability that a randomly selected college student will take between 4.0 and 6.5 minutes to find aparking spot in the library lot.
The length of time it takes college students to find a parking spot in the library parking lot follows a normal distribution with a mean of 4.0 minutes and a standard deviation of 1 minute. Find the probability that a randomly selected college student will take between 2.5 and 5.0 minutes to find a parking spot in the library lot.
A random sample of 65 high school students has a normal distribution. The sample mean average ACT exam score was 21.4 with a 3.2 sample standard deviation. Construct a 90% confidence interval estimate of the population mean average ACT exam.
The time required for Dr. B's students to complete the Statistics Exam is approximately normally distributed with a mean of 40.4 minutes and a standard deviation of 2.2 minutes. Let X be the random variable "the time required for Dr. B's students to complete the Statistics Exam." 6. With the above setting what time marks the 90th percentile? A. 37.562 minutes B. 37.584 minutes C. 43.238 minutes D. 43.216 minutes E. None of the above 7. Which of the following...
The grade point averages of the students in a large statistics class follow a normal distribution with a mean of 3.0 and a standard deviation of 0.25. What is the probability that a randomly sampled student from this class has a GPA of less than 2.95? (hint: you will need to use the table on page 175)
The scores on a statistics exam had an approximately normal distribution, with a mean of 73 and standard deviation of 7.2. If a single student is chosen at random, what is the probability their score is less than 74?