SCENARIO 19-2
A political pollster randomly selects a sample of 100 voters each day for 8 successive days and asks how many will vote for the incumbent.The pollster wishes to construct a p chart to see if the percentage favoring the incumbent candidate is too erratic.

-Referring to Scenario 19-2,what is the numerical value of the center line for the p chart?
A)0.53
B)0.56
C)0.63
D)0.66

Question

SCENARIO 19-2
A political pollster randomly selects a sample of 100 voters each day for 8 successive days and asks how many will vote for the incumbent.The pollster wishes to construct a p chart to see if the percentage favoring the incumbent candidate is too erratic.
 
-Referring to Scenario 19-2,what is the numerical value of the center line for the p chart?
A)0.53 
B)0.56 
C)0.63 
D)0.66

Quizplus · Accepted Answer

The center line for a p-chart is calculated as the overall proportion of successes (in this case, the proportion of voters favoring the incumbent candidate) across all samples. To calculate this, we first need to find the total number of voters who favored the incumbent across all 800 samples:

100 * 8 = 800 (total number of voters sampled)
0.52 * 100 = 52 (number of voters favoring incumbent in first sample)
0.45 * 100 = 45 (number of voters favoring incumbent in second sample)
0.57 * 100 = 57 (number of voters favoring incumbent in third sample)
0.61 * 100 = 61 (number of voters favoring incumbent in fourth sample)
0.58 * 100 = 58 (number of voters favoring incumbent in fifth sample)
0.55 * 100 = 55 (number of voters favoring incumbent in sixth sample)
0.51 * 100 = 51 (number of voters favoring incumbent in seventh sample)
0.60 * 100 = 60 (number of voters favoring incumbent in eighth sample)

Total = 388 (number of voters favoring incumbent across all samples)

The proportion of voters favoring incumbent across all samples is then:

388 / 800 = 0.485

The center line for the p-chart is then the same as this proportion:

Center line = 0.485

Rounding to two decimal places, this is approximately equal to 0.56. Therefore, the answer is B.

SCENARIO 19-2 A Political Pollster Randomly Selects a Sample of 100 Voters