statistics
posted by Emmanuel .
a study of 40 professors showed they spent on average 13.6 minutes correcting a student papers. Given a standard deviation of 17, the 90% confidence interval of the mean time for all the test papers is what?

Formula:
CI90 = mean + or  1.645(sd/√n)
With your data:
CI90 = 13.6 + or  1.645(17/√40)
I'll let you take it from here.
Respond to this Question
Similar Questions

statistics
To test the hypothesis that students who finish an exam first get better grades, Professor Hardtack kept track of the order in which papers were handed in. The first 25 papers showed a mean score of 77.1 with a standard deviation of … 
res/342
To test the hypothesis that students who finish an exam first get better grades, Professor Hardtack kept track of the order in which papers were handed in. The first 25 papers showed a mean score of 77.1 with a standard deviation of … 
statistics
A study of 40 psychology teachers showed that they spent, on average, 12.6 minutes correcting a student's final term paper. Find the 90 percent confidence interval of the mean time for all psychology teachers correcting final term … 
ELEMENTARY STATISTICS
50 MATH PROFESSORS WERE ASKED HOW LONG IT TAKES TO GRADE A STUDENT'S HOMEWORK ASSIGNMENT. THE MEAN GRADING TIME FOR THE SAMPLE WAS 36.2 MINUTES WITH A STANDARD DEVIATION OF 4.8 MINUTES. WHAT IS THE 99% CONFIDENCE INTERVAL FOR THE MEAN … 
UOP
o test the hypothesis that students who finish an exam first get better grades, Professor Hardtack kept track of the order in which papers were handed in. The first 25 papers showed a mean score of 77.1 with a standard deviation of … 
statistics
A sample of 400 high school students showed that they spend an average of 70 minutes a day watching television with a standard deviation of 14 minutes. Another sample of 500 college students showed that they spend an average of 55 … 
statistics
A study of 35 professors showed that the average time they spent creating test questions was 13.5 minutes per question. The standard deviation of the population is 3.8. Which of the following is the 99% confidence interval for the … 
Beginning of Stats
A study of 50 mathematics professors showed that they spend, on average,12.4 minutes correcting a student's final examinations. Find a 90% confidence interval of the mean time for all mathematics peofessors spend on conrrecting final … 
Statistics
1. A study of 40 people found that they could do on the average15 pull ups with a standard deviation of .6. Find the 99% confidence interval for the mean of the population. 2. A study of 50 pizza delivery workers found that they could … 
statistics
A sample of 40 CDs from a student's collection showed a mean length of 52.74 minutes with a standard deviation of 13.21 minutes. Construct a 95% confidence interval for the population standard deviation. (Round your answers to 4 decimal …