Confidence interval-state education agency

Reference no: EM13104598

A state education agency designs and administers high school proficiency exams. Historically, time to complete the exam was an average of 120 minutes. Recently the format of the exam changed and the claim has been made that the time to complete the exam has changed. A sample of 50 new exam times yielded an average time of 118 minutes. The standard deviation is assumed to be 5 minutes. Calculate a 99% confidence interval.

[117.61 120.09]

[117.36 119.39]

[116.18 119.82]

[115.67 120.33]

[115.82 120.18]

Reference no: EM13104598

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