Question

Question 6 (1 point)

Pinterest claims that 0.3744 of their app users are men. In a sample of 70 randomly chosen app users, what is the probability that at least 23 of them will be men?

Question 6 options:

1)

0.2538

2)

0.7462

3)

0.8196

4)

0.0367

5)

0.0734

Answer 1

Mean = n * P = ( 70 * 0.3744 ) = 26.208
Variance = n * P * Q = ( 70 * 0.3744 * 0.6256 ) = 16.3957
Standard deviation = = 4.0492

P ( X >= 23 )
Using continuity correction
P ( X > n - 0.5 ) = P ( X > 23 - 0.5 ) =P ( X > 22.5 )

P ( X > 22.5 ) = 1 - P ( X < 22.5 )
Standardizing the value

Z = ( 22.5 - 26.208 ) / 4.0492
Z = -0.92

P ( Z > -0.92 )
P ( X > 22.5 ) = 1 - P ( Z < -0.92 )
P ( X > 22.5 ) = 1 - 0.1804
P ( X > 22.5 ) = 0.8196