As part of a class project, Sarah and Geoffrey conducted a survey asking their peers whether they planned on taking a music class the next year. of the 90 students they surveyed, 43 responded favorably. Sarah and Geoffrey calculated the margin of error for different confidence intervals.
Their work is shown.
Sarah
Geoffrey
95% confidence:
90% confidence
0.48(1 - 0.48
ME = 1.96 V
90
(8) 1 - 3
ME = 1.65V
133
Which student incorrectly found the margin of error and why?
O A Geoffrey incorrectly found the margin of error because he used the wrong critical value.
OB. Geoffrey incorrectly found the margin of error because he used the wrong sample size.
OC. Sarah incorrectly found the margin of error because she used the wrong sample proportion.
OD. Sarah incorrectly found the margin of error because she used the wrong critical value.