Respuesta :
Answer:
The probability is 0.2356.
Step-by-step explanation:
Let X is the event of using the smartphone in meetings or classes,
Given,
The probability of using the smartphone in meetings or classes, p = 51 % = 0.51,
So, the probability of not using smartphone in meetings or classes, q = 1 - p = 1 - 0.51 = 0.49,
Thus, the probability that fewer than 5 of them use their smartphones in meetings or classes.
P(X<5) = P(X=0) + P(X=1) + P(X=2) + P(X=3)+P(X=4)
Since, binomial distribution formula is,
[tex]P(x) = ^nC_r p^x q^{n-x}[/tex]
Where, [tex]^nC_r=\frac{n!}{r!(n-r)!}[/tex]
Here, n = 11,
Hence, the probability that fewer than 5 of them use their smartphones in meetings or classes
[tex]=^{11}C_0 (0.5)^0 0.49^{11}+^{11}C_1 (0.5)^1 0.49^{10}+^{11}C_2 (0.5)^2 0.49^{9}+^{11}C_3 (0.5)^3 0.49^{8}+^{11}C_4 (0.5)^4 0.49^{7} [/tex]
[tex]=(0.5)^0 0.49^{11}+11(0.5)0.49^{10} + 55(0.5)^2 0.49^{9}+165 (0.5)^3 0.49^{8} +330(0.5)^4 0.49^{7} [/tex]
[tex]=0.235596671797[/tex]
[tex]\approx 0.2356[/tex]
