Question

1) Assume that when adults with smartphones are randomly selected, 53% use them in meetings or classes. If 10 adult smartphone users are randomly selected, find the probability that at least 5 of them use their smartphones in meetings or classes.(Round to 4 decimal places as needed)

2) Assume that when adults with smartphones are randomly selected, 46% use them in meetings or classes. If 11 adult smartphone users are randomly selected, find the probability that fewer than 5 of them use their smartphones in meetings or classes.(An integer or decimal rouended to 4 decimal places)

Answer 1

1)

Answer)

As there are fixed number of trials and probability of each and every trial is same and independent of each other.

Here we need to use the binomial formula.

P(r) = ncr*(p^r)*(1-p)^n-r

Ncr = n!/(r!*(n-r)!)

N! = N*n-1*n-2*n-3*n-4*n-5........till 1

For example 5! = 5*4*3*2*1

Special case is 0! = 1

P = probability of single trial = 0.53

N = number of trials = 10

R = desired success = at least 5.

= P(5) + P(6) + P(7) + P(8) + P(9) + P(10).

= 0.69432281703