Question

you are given 20 true false question and required to find the probability of atleast 4 correct​

Answer 1

Answer:

=0.0046205520629883

Step-by-step explanation:

P(4)= 20!/(20-4)! 4! X 0.5⁴ x 0.5¹⁶

= 20!/16! 4! X 0.5⁴ X 0.5¹⁶

= (20 x 19 x 18 x 17 x 16!)/ 16!4! X 0.5⁴ X 0.5¹⁶

= (20 X 19 X 18 X 17)/4! X 0.5⁴ X 0.5¹⁶

= (20 X 19 X 18 X 17)/ (4 X 3 X 2) X 0.5⁴ X 0.5¹⁶

= (5 X 19 X 3 X 17) X 0.5⁴ X 0.5¹⁶

=4845 x 0.5⁴ x 5¹⁶

=0.0046205520629883