A test-scoring machine is known to record an incorrect grade on 5 ...

[kellyjaisingh]

A test-scoring machine is known to record an incorrect grade on 5 of the exams it grades. Find by the appropriate method, the probability that the machine records no more than 2 wrong grades in a set of 15 exams.

Question 2

A test-scoring machine is known to record an incorrect grade on 5 of the exams it grades. Find by the appropriate method, the probability that the machine records no more than 2 wrong grades in a set of 10 exams.

[sultansheikh]

Answer to Question 1

P(no more than 2 wrong in 15) = Px = 0,1, 2  B (n = 15, p = 0.05)
= 0.463 + 0.366 + 0.135 = 0.964

Answer to Question 2

P(no more than 2 wrong in 10) = Px = 0, 1, 2  B(n = 10, p = 0.05)
= 0.599 + 0.315 + 0.075 = 0.989

[kellyjaisingh]

Great answer, keep it coming

[Sarahjh]

Excellent