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Algebra scores in a school district are approximately normally distributed with mean μ = 72 and...

Algebra scores in a school district are approximately normally distributed with mean μ = 72 and standard deviation σ = 5. A new teaching-and-learning system, designed to increase average scores, is introduced to a random sample of 36 students, and in the first year the average was 73.5.

(a) What is the probability that an average as high as 73.5 would have been obtained under the old system?

(b) Is the test significant at the 0.05 level? What about the 0.01 level? Explain your answers.

Math   Statistics-And-Probability   
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