Posted by Tricia on Sunday, April 15, 2012 at 7:43am.
Mean score of tests :
( x1 + x2 + x3 + x4 + x5 ) / 5 = 88 Multiply both sides by 5
x1 + x2 + x3 + x4 + x5 = 88 * 5
x1 + x2 + x3 + x4 + x5 = 440
Mean score of six tests :
( x1 + x2 + x3 + 4 + x5 + x6 ) / 6 = 80
[ ( x1 + x2 + x3 + 4 + x5 ) + x6 ] / 6 = 80
( 440 + x6 ) / 6 = 80 Multiply both sides by 6
440 + x6 = 80 * 6
440 + x6 =480
x6 = 480 - 440
x6 = 60
( x1 + x2 + x3 + x4 + x5 + x6 ) / 6 = 80
x6 = 480 - 440
x6 = 40
Related Questions
Math - To get an A in psychology, a student must score an average of 90 on four ...
Math - On a test whose distribution is approximately normal with a mean of 50 ...
math - To get a C in physics, a student must score an average of 70 on four ...
Stasistic - On a test whose distribution is approximately normal with a mean of ...
algebra - sasha needs to score at least 360 points on 4 tests to earn an A. on ...
Statistics - Suppose that two different tests A and B are to be given to a ...
Math - You have a mean score of 86 on 9 quizzes. The teacher decides to drop ...
statistics - Calculate the z-score for each set of data. Determine who did ...
math - To get an A in history, a student must score an average of 90 on four ...
MATH - Katie must take five exams in a math class. Her scores on the first four ...
For Further Reading
