Estimating the Difference between Two Population Proportions
Question 10 • CA-Statistics and Probability B
In a statistics activity, students are asked to determine if there is a difference in the proportion of times that a spinning penny will land with tails up, and the proportion of times a spinning dime will land tails up. The students are instructed to spin the penny and the dime 30 times and record the number of times they land tails up. For one student, the penny lands tails side up 18 times, and the dime lands tails side up 20 times. Assuming the conditions for inference are met, what is the 98% confidence interval for the difference in proportions of tails side up for a penny and a dime?Find the z-table here.
Answer
A
(0.40 minus 0.33) plus-or-minus 2.33 StartRoot StartFraction 0.40 (1 minus 0.40) Over 30 EndFraction + StartFraction 0.33 (1 minus 0.33) Over 30 EndFraction EndRoot
B
(0.40 minus 0.33) plus-or-minus 2.58 StartRoot StartFraction 0.40 (1 minus 0.40) Over 30 EndFraction + StartFraction 0.33 (1 minus 0.33) Over 30 EndFraction EndRoot
C
(0.60 minus 0.67) plus-or-minus 2.33 StartRoot StartFraction 0.60 (1 minus 0.60) Over 30 EndFraction + StartFraction 0.67 (1 minus 0.67) Over 30 EndFraction EndRoot
D
(0.60 minus 0.67) plus-or-minus 2.58 StartRoot StartFraction 0.60 (1 minus 0.60) Over 30 EndFraction + StartFraction 0.67 (1 minus 0.67) Over 30 EndFraction EndRoot