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.0000 Sprint a webwork.uoregon.edu webwork/math243summer-pohland / chapter3 /8 C

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Question

.0000 Sprint a webwork.uoregon.edu webwork/math243summer-pohland / chapter3 /8 Chapter3: Problem 8 Previous Problem List Next (1 point) Find the value z of a standard Normal variable that satisfies each of the following conditions (a) The point z with 10% of the observations falling below it (b) The point z with 50% of the observations falling above it Note: You can earn partial credit on this problem. Preview My Answers Submit Answers You have attempted this problem 0 times. You have unlimited attempts remaining.

Explanation / Answer

Chapter 3 Problem 8

a) Z=-1.28 .....................by using NORMSINV(0.10) or normal probability table.

The z-critical value for a left-tailed test, for a significance level of =0.10 is zc=1.28

b) Z=0

The z-critical value for a right-tailed test, for a significance level of =0.50 is zc=0

Chapter 8 Problem 3

a) We know that,

Approximately 68% of the observations fall within 1 standard deviation of the mean.

Therefore, (7.12-0.79, 7.12+0.79) = > (6.33 , 7.91)

From 6.33 minutes to 7.91 minutes.

b) P[X<5.54]   = P[Z<(5.54-7.12)/0.79 ]

                       = P[Z<-2]

                       = 0.0228........................by using normal probability table.

Therefore, 2.28% of these men run a mile in less than 5.54 minutes.