I. In a national mathematics standard test for third graders yielded national av

Question

I. In a national mathematics standard test for third graders yielded national average -210 points with standard deviation =40 point. Model the result as a normal distribution. Answer the following questions: Mary scored 216, what percentile she is? Mary's school has 360 students had school average score 216, what the percentile of her school among all the schools with around 360 students? Do you think that was likel for a school with 360 students to have average 216? Explain Would a school of size 64 students tell a different story? a. b. c.

Explanation / Answer

a)correct

b)

here std error =std deviation/(n)1/2 =40/(360)1/2 =2.1082

therefore percentile of school =normdist(216,210,2.1082,true)=0.9978 ~ 99.78%

It is likely but very less college can acheive that

c)

for sample size n=64 ; std error of sample mean would be different therefore it will tell different story.

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