Statistics
posted by robyn
On a chemistry exam, Student A scored a 81 and Student B scored a 70. The mean for the class was 75 and the standard deviation was 3.8.
What percentage of students scored in somewhere in between Student A and Student B?

bobpursley
about 15 percent if you believe it was a normal distribution. Seldom it is.
http://davidmlane.com/hyperstat/z_table.html 
PsyDAG
Here is another method.
If it approximates a normal distribution, you can use
Z = (scoremean)/SD
Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportions related to the Z scores.
Respond to this Question
Similar Questions

statistics and probability
It is known that an exam scores of students in STAT 2507 follow a normal distribution with a mean of 70% and a standard deviation of 9%. (A) If a student must obtain a mark of 50% to pass the exam, what proportion of students fail … 
Statistics Math
One student scored 54 on a math test for which the mean score was 50.5 and the standard deviation was 3.2. Another student scored 80 on a chemistry test for which the mean score was 75.2 and the standard deviation was 5.2. Which student … 
Math
First period: 85, 83, 74, 70, 88,95,89,72,90,83,77,91,98,89,82,84 Second period: 95,89,82,81,72,69,100,97,75,91,82,79,96,81,80,95,89,97,83,71 Mark is a student in the first period class. His score on the exam was 95%. Zoe is a student … 
CRJ303Statistics question
Reworded from the "Study Questions" part of Chapter 5 from this site: "Student Study Site for Essentials of Social Statistics for a Diverse Society" Please show the steps for each question "When the Scholastic Aptitude Test (SAT) … 
stats
Relatively speaking, which statistics exam did you do better on? 
Statistics
If student A scored 42 on a test of reading and the test had a mean of 52 and a standard deviation of 8, what percentage of test respondents scored below student A? 
probability and statistics
Suppose every student in your class got a score of 85% on an exam. What are the mean and standard deviation of those exam scores without doing any calculations? 
Algebra
Over 350 students took a college calculus final exam. the scores of the students follow a normal distribution. using the information given below, determine the mean and the standard deviation for the students'scores. Give your answers … 
Statistics
Two high school students took equivalent language tests, one in German and one in French. The student taking the German test, for which the mean was 66 and the standard deviation was 8, scored an 82, while the student taking the French … 
Maths
There are fifty students in a class. In a 100 marks exam, 20 students scored less than 30 marks, 5 students scored more than 70 marks and the remaining scored between 30 and 70 marks. If passing score is 55 marks and 40% students have …