Respuesta :
Answer:
c. an observed difference is 0.12 and P < 0.0001
Step-by-step explanation:
Let p1 be the proportion of the students who received musical instruction received a passing grade
Let p2 be the proportion of the students who didn't receive musical instruction received a passing grade
Null and Alternative hypotheses are:
- [tex]H_{0}[/tex]: p1-p2=0
- [tex]H_{a}[/tex]: p1-p2≠0
Test statistic can be found using the equation:
[tex]z=\frac{p1-p2}{\sqrt{{p*(1-p)*(\frac{1}{n1} +\frac{1}{n2}) }}}[/tex] where
- p1 is the sample proportion of the students who received musical instruction received a passing grade ([tex]\frac{2818}{3239} =0.87[/tex])
- p2 is the sample proportion of the students who didn't receive musical instruction received a passing grade ([tex]\frac{2091}{2787} =0.75[/tex])
- p is the pool proportion of p1 and p2 ([tex]\frac{2818+2091}{6026}=0.81[/tex])
- n1 is the sample size of the students who received musical instruction (3239)
- n2 is the sample size of the students who didn't receive musical instruction (2787)
Thus, [tex]z=\frac{0.87-0.75}{\sqrt{{0.81*0.19*(\frac{1}{3239} +\frac{1}{2787}) }}}[/tex] ≈ 11.84 gives p-value < 0.0001
Observed difference is: 0.87-0.75=0.12