14.6 A superintendent of schools is interested in revising the curriculum.

He sends out questionnaires to 200 teachers: 100 respond No to the question ‘‘do you think we should revise the curriculum?’’

The superintendent then held a weeklong workshop on curriculum improvement and sent the same questionnaire to the same 200 teachers; this time 90 responded No. Eighty teachers responded No both times. Investigate whether the workshop significantly decreased the number of negative responses.