Question

A population of components when testing high laboratory stresses fails according to a lognormal distribution with T50 = 5000 and σ = 0.7. What percentage of failures are expected at 2000 hours of testing?

Solve it in Minitab

Answer 1

given data are:-

some necessary calculations:-

(where, is the location parameter of lognormal distribution.)

the scale parameter () = 0.7

the percentage of failures are expected at 2000 hours of testing be:-

%

%

%

[ as instructed i am using minitab.

steps:-

calc probability distributions select lognormal distribution select cumulative probability ,in location type 8.517193, in scale type 0.7,in threshold type 0 select input constant, type 2000 ok.

your output be:-

Lognormal with location = 8.51719 and scale = 0.7

x	P( X ≤ x )
2000	0.0952702

]

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