SCENARIO 18-2
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. $$\begin{array} { c c }
\begin{array} { c }
\text { Sample } \
\underline{\text { (Day) }}
\end{array} & \begin{array} { c }
\text { Number Favoring } \
\underline{\text { Incumbent Candidate }}
\end{array} \
1 & 57 \
2 & 57 \
3 & 53 \
4 & 51 \
5 & 55 \
6 & 60 \
7 & 56 \
8 & 59
\end{array}$$
-Referring to Scenario 18-2, what is the numerical value of the lower control limit for the p chart?
A) 0.37
B) 0.41
C) 0.50
D) 0.71

Question

SCENARIO 18-2
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. $$\begin{array} { c c } 
\begin{array} { c } 
\text { Sample } \
\underline{\text { (Day) }}
\end{array} & \begin{array} { c } 
\text { Number Favoring } \
\underline{\text { Incumbent Candidate }}
\end{array} \
 1 & 57 \
2 & 57 \
3 & 53 \
4 & 51 \
5 & 55 \
6 & 60 \
7 & 56 \
8 & 59
\end{array}$$
-Referring to Scenario 18-2, what is the numerical value of the lower control limit for the p chart?
A) 0.37
B) 0.41
C) 0.50
D) 0.71

Quizplus · Accepted Answer

The lower control limit (LCL) for a p chart is calculated using the formula: LCL = p̄ - 3√(p̄(1-p̄)/n), where p̄ is the average proportion and n is the sample size. Here, p̄ = (57+57+53+51+55+60+56+59)/800 = 0.56. Thus, LCL = 0.56 - 3√(0.56(1-0.56)/100) ≈ 0.41.

SCENARIO 18-2 a Political Pollster Randomly Selects a Sample of 100

SCENARIO 18-2
a Political Pollster Randomly Selects a Sample of 100