Suppose a geyser has a mean time between eruptions of 72 minutes. If the interval of time between the eruptions is normally distributed with standard deviation 21 minutes, answer the following questions.

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Question

Suppose a geyser has a mean time between eruptions of 72 minutes. If the interval of time between the eruptions is normally distributed with standard deviation 21 minutes, answer the following questions. 

See attachment.

anonymous · Answer

attachment

anonymous · Answer

do i start with $$z=\frac{ x-\mu }{ \sigma } $$

amistre64 · Answer

that will tell you the standardized z score yes

amistre64 · Answer

what do you have at your disposal for this ... tabels, ti83, stat program?

anonymous · Answer

z=81-72/21=0.43

z=0.43=0.666402

do i use 1-0.666402=0.333598 as my answer or just leave it as 0.666402?

anonymous · Answer

i use http://www.fourmilab.ch/rpkp/experiments/analysis/zCalc.html and http://sampson.byu.edu/courses/z2p2z-calculator.html

amistre64 · Answer

since 81 is greater than 72; any probability that is cumulative of 81 and more has to be less than 50% by default

amistre64 · Answer

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