for a final exam in statistics , the mean of the exam scores is u= 75...

for a final exam in statistics , the mean of the exam scores is u= 75 with a standard deviation of o=8. what sample mean marks the top 10% of this distribution for a samples of n= 25

b) what sample means mark the boundaries of the middle 50% for samples of n= 50

Expert Solution

orchestra answered 2 years ago

You were told that the mean score on a statistics exam is 75 with the scores...

You were told that the mean score on a statistics exam is 75 with the scores normally distributed. In addition, you know the probability of a score between 55 and 60 is 4.41% and that the probability of a score greater than 90 is 6.68%. What is the probability of a score between 55 and 95?

The final exam scores in a statistics class were normally distributed with a mean of 70...

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 less than 55% on the exam?

Below are the final exam scores of 20 Introductory Statistics students.

Below are the final exam scores of 20 Introductory Statistics students. Student 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Score 71 76 77 77 79 80 80 80 81 81 84 84 85 86 86 86 86 87 89 93 The mean exam score is 82.4 with a standard deviation of 5.14. 1. How many of the exam scores in the sample are within one standard deviation...

The following are final exam scores for 30 students in an elementary statistics class.

The following are final exam scores for 30 students in an elementary statistics class. 91 59 82 91 79 76 90 69 77 83 59 88 95 72 88 81 77 52 80 96 62 97 76 75 75 89 61 72 90 85 a. Find the quartiles for this data______________________________. b. What is the Interquartile Range (IQR)_________________________? c. What percent of students got at least a 72 on their final exam______________? d. Build a boxplot using the graphing calculator.

A sample of 10 students record their scores on the final exam for their statistics class....

A sample of 10 students record their scores on the final exam for their statistics class. The mean of the sample is 81 with sample standard deviation 7 points. Analysis of the 10 sample values indicated that the population is approximately normal. We wish to find the 95% confidence interval for the population mean test scores. 1. What is the confidence level, c? 2. Which of the following is correct? a. To find the confidence interval, a z-critical value should...

A) Suppose that the mean and standard deviation of the scores on a statistics exam are...

A) Suppose that the mean and standard deviation of the scores on a statistics exam are 89.2 and 6.49, respectively, and are approximately normally distributed. Calculate the proportion of scores below 77. 1) 0.0301 2) 0.9699 3) We do not have enough information to calculate the value. 4) 0.2146 5) 0.7854 B) When students use the bus from their dorms, they have an average commute time of 8.974 minutes with standard deviation 3.1959 minutes. Approximately 66.9% of students reported a...

Given the scores on a certain exam are normally distributed with a mean of 75 and...

Given the scores on a certain exam are normally distributed with a mean of 75 and a standard deviation of 5 a. Calculate the z-score for 80. Find the percentage of students with scores above 80 b. Calculate the z-score for 60. Find the percentage of students with scores below 60. c. Calculate the z-scores for 70 and 90. Find the percentage of students with scores between 70 and 90. d. What is the median? e. What test score value...

Exam grades: Scores on a statistics final in a large class were normally distributed with a...

Exam grades: Scores on a statistics final in a large class were normally distributed with a mean of 70 and a standard deviation of 10. Use the TI-84 PLUS calculator to answer the following. Round the answers to at least two decimals. (a) Find the 42nd percentile of the scores. (b) Find the 71st percentile of the scores. (c) The instructor wants to give an A to the students whose scores were in the top 10% of the class. What...

A sample of final exam scores is normally distributed with a mean equal to 29 and...

A sample of final exam scores is normally distributed with a mean equal to 29 and a variance equal to 25. Part (a) What percentage of scores are between 24 and 34? (Round your answer to two decimal places.) Part (b) What raw score is the cutoff for the top 10% of scores? (Round your answer to one decimal place.) Part (c) What is the proportion below 23? (Round your answer to four decimal places.) Part (d) What is the...

A sample of final exam scores is normally distributed with a mean equal to 25 and...

A sample of final exam scores is normally distributed with a mean equal to 25 and a variance equal to 16. Part (a) What percentage of scares are between 21 and 29? (Round your answer to two decimal places) Part (b) What raw score is the cutiff for the top 10% of scores? (Round your answer to one decimal place) Part (c) What is the proportion below 20? (Round your answer to four decimal places) Part (d) What is the...

Question