The reading speed of second grade students in a large city is approximately norm

ID: 3216862 • Letter: T

Question

The reading speed of second grade students in a large city is approximately normal, with a mean of

89 words per minute (wpm) and a standard deviation of 10 wpm. Complete parts (a) through (c).

(a) What is the probability a randomly selected student in the city will read more than

93 words per minute?

(b) What is the probability that a random sample of

13 second grade students from the city results in a mean reading rate of more than

93 words per minute?

The probability is ?

nothing??.

(Round to four decimal places as needed.)

26 second grade students from the city results in a mean reading rate of more than 93words per minute ?

The probability is ?

Solution:- given values mean = 89 and standard deviation = 10

a) z(93) = (93-89)/10 = 0.4

P(x > 93) = P(z > 0.4) = 0.3446

b) z(93) = (93-89)/1013

= 4/2.7735 = 1.4422

P(x > 93) = P(z > 1.4422) = 0.0749

c) z(93) = (93-89)/1026

= 4/1.9611 = 2.0397

P(x > 93) = P(z > 2.0397) = 0.0207

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