<span>18z-7(-3+2z)
= 18z + 21 - 14z
= 4z + 21
answer is False
</span><span>coefficient of z is 4, not 13</span>
Solution :
Group Before After
Mean 693.75 743.75
Sd 155.37 143.92
SEM 54.93 50.88
n 8 8
Null hypothesis : The preparation course not effective.

Alternative hypothesis : The preparation course is effective in improving the exam scores.
(after - before)
Find the sum of the interior angles of a 22-gon. Since the polygon has 22 sides, we can substitute this number for n: (n 2)180˚= (22 2)180˚= 20180˚= 3600˚. Each angle of a regular polygon measures 157.5˚.
-19 + (-12) = 7
Remove Parentheses
( -a ) = -a
= 19 - 12
Subtract The Numbers
19-12 = 7