algebra 2
posted by Lea .
Students at a high school all took the same English test. The scores are approximately normally distributed with a mean of 77 and a standard deviation of 9. If 2500 students took the test, approximately how many scored above 86 or below 68%?

you buy a video game system for $500. the value of the video game system system decreases 25% each year . write an exponential model for the value of the videogame system in terms of the yeArs since the purchase
Respond to this Question
Similar Questions

statistics
In a psychology class of 100 students, test scores are normally distributed with a mean of 80 and a standard deviation of 5. Approximately what percentage of students have scores between 70 and 90? 
statistics!
1) Entry to a certain University is determined by a national test. The scores on this test are normally distributed with a mean of 500 and a standard deviation of 100. Tom wants to be admitted to this university and he knows that he … 
graduate statistics
A nursing professor was curious as to whether the students in a very large class she was teaching who turned in their tests first scored differently from the overall mean on the test. The overall mean score on the test was 75 with … 
Statistics
The scores for math test #3 were normally distributed. If 15 students had a mean score of 74.8% and a standard deviation of 7.57, how many students scored above an 85%? 
statistics
The scores for math test #3 were normally distributed. If 15 students had a mean score of 74.8% and a standard deviation of 7.57, how many students scored above an 85%? 
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 … 
Algebra
I do not understand this homework at all. Any help or elaboration would be greatly appreciated. Thanks. 100 juniors at Southwest High took the SAT test. The scores were distributed normally with a mean of 22 and a standard deviation … 
Algebra
Scores on a statewide standardized test are normally distributed with a mean of 12.89 and a standard deviation of 1.95. Certificates are given to students whose scores are in the top 2% of those who took the test. This means that they … 
statistics
10th grade New York public school students taking a standardized English test produced test scores that were normally distributed with a mean of 85 and a standard deviation of 4. Let x be a random variable that represents the test …