Question

78% of all laboratory mice fed GMO diet develop cancer within a year. If 600 laboratory mice fed GMO diet are randomly selected, what is the probability that more than 80% of them will develop cancer within a year?

Answer 1

Given : n = 600 , p = 0.78

Mean () = np  

= 600(0.78) = 468.

Standard deviation () =

=

= = 10.147

P( more than 80%)

80% of 600 = 0.8*600 = 480

P(x > 480 ) = 1 - P( x 480)

Using approximation method,

P( x a) =

Thus, P( x > 480) = 1 -

= 1 -

= 1 -  

= 1 - 0.8907

= 0.1093

Thus, there is 0.1093 Probability that more than 80% will develop cancer within a year.

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