The manager of a pharmacy wants to know if prescriptions are filled uniformly over the 7 days of the week. The manager takes a simple random sample of 245 prescription receipts and finds that they are distributed as follows:
$$\begin{array} { | l | c | c | c | c | c | c | c | }
\hline \text { Day } & \text { Monday } & \text { Tuesday } & \text { Wednesday } & \text { Thursday } & \text { Friday } & \text { Saturday } & \text { Sunday } \
\hline \text { Prescriptions } & 42 & 31 & 33 & 29 & 45 & 44 & 21 \
\hline
\end{array}$$ What is the chi-square statistic for the null hypothesis of a uniform distribution of prescriptions over the 7 days of the week?

Question

The manager of a pharmacy wants to know if prescriptions are filled uniformly over the 7 days of the week. The manager takes a simple random sample of 245 prescription receipts and finds that they are distributed as follows:
$$\begin{array} { | l | c | c | c | c | c | c | c | } 
\hline \text { Day } & \text { Monday } & \text { Tuesday } & \text { Wednesday } & \text { Thursday } & \text { Friday } & \text { Saturday } & \text { Sunday } \
\hline \text { Prescriptions } & 42 & 31 & 33 & 29 & 45 & 44 & 21 \
\hline
\end{array}$$ What is the chi-square statistic for the null hypothesis of a uniform distribution of prescriptions over the 7 days of the week?

Quizplus · Accepted Answer

The chi-square statistic is calculated by comparing the observed frequencies with the expected frequencies under the null hypothesis of uniform distribution. The expected frequency for each day is 245/7 = 35. The chi-square statistic is the sum of ((observed - expected)^2 / expected) for each day, which equals 13.8.

The Manager of a Pharmacy Wants to Know If Prescriptions