the reading speed of second grade students is approximately normal, with a mean

Question

the reading speed of second grade students is approximately normal, with a mean of 88 words per minute, standard deviation of 10 words per minute.

Need help with B

The mading speed of second grade (a) What is the probabiity a randomly selncted sAudent road mom than The probability is 274 Round to four decímal places as needed) (b) What is the probatdlity that a randorn sample of 10 second grade nhudents neuts in a rean eading e of mase than 94 words e The probability is Round to four decimal places as needed)

Explanation / Answer

WE HAVE MEAN = 88

STANDARD DEVIATION = 10

B) HERE WE NEED TO FIND P(X>94)

THE Z = (X - MEAN)/STANDARD DEVIATION

Z = (94-88)/10 = 0.6

THE P VALUE FOR Z = 0.6 = 0.7257

NOW P(X>94) = 1 - 0.7257 = 0.2743

SO IF WE HAVE 10 STUDENTS SAMPLE ONLY APROX 3 STUDENTS WILL READ MORE THEN 94 WORDS.

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