assume that when adults with smartphones are randomly selected 52% use them in meetings or classes. if 12 adult smartphone users are randomly selected find the probability that fewer than 4 of them use their smartphones in meetings or classes?

0.056

Step-by-step explanation:

Use binomial probability:

P = nCr pʳ qⁿ⁻ʳ

where n is the number of trials,

r is the number of successes,

p is the probability of success,

and q is the probability of failure (1−p).

P(r<4) = P(0) + P(1) + P(2) + P(3)

P(r<4) = ₁₂C₀ (0.52)⁰ (0.48)¹²⁻⁰ + ₁₂C₁ (0.52)¹ (0.48)¹²⁻¹ + ₁₂C₂ (0.52)² (0.48)¹²⁻² + ₁₂C₃ (0.52)³ (0.48)¹²⁻³

P(r<4) = (0.48)¹² + 12 (0.52) (0.48)¹¹ + 66 (0.52)² (0.48)¹⁰ + 220 (0.52)³ (0.48)⁹

P(r<4) = 0.056

the entire expression should be subtracted from 30. to subtract the quantity, distribute the negative sign, which changes the signs on the terms. so, the –2 changes to positive and gets added to 30 instead of subtracted from it.

hope this ! ^w^

answer: i'm not going to give you the answer, but some hints to work it out.

step-by-step explanation: so, if there is a straight line that means that the line angle is 180°. so we subtract the 2 angle measures provided, (15 and 38) from 180. so the answer is 180 - (38 + 15). (you have to solve the equation)