Answer to Question #152647 in Statistics and Probability for Shavetra

Question

The school board is trying to evaluate a new math program introduced to second- graders in five elementary schools across the county this year. A sample of the student
scores on standardized math tests in each elementary school yielded the following data:
SCHOOL NO OF TEST ERRORS
A 52
B 27
C 35
D 44
E 55
Construct a c-chart for test errors, and set the control limits to contain 99.73% of the
random variation in test scores. What does the chart tell you? Has the new math program
been effective

Answer 1

The chart tells us that all the points are between the upper and lower control limits, so the process is under control. Since the process under control, the number of defects is controlled and we know with a 99.3 % of certainty the average of them, so the program is effective.