Question

63 % of U.S. adults have very little confidence in newspapers. You randomly select 10 U.S. adults. Find the probability that the number of U.S. adults who have very little confidence in newspapers is (a) exactly five, (b) at least six, and (c) less than four.

(a) P(5)=____ (Round to three decimal places as needed.)

(b) P(x greater than or equals 6)=_____ (Round to three decimal places as needed.)

(c) P(x< 4)=___ (Round to three decimal places as needed.)

Answer 1

Given:

Therefore , the pmf of X is ,

; x=0,1,2,...........,n

= 0 ; otherwise

The table for probability is ,

x
0	1	1	4.80858E-05	4.80858E-05
1	10	0.63	0.000129962	0.000818759
2	45	0.3969	0.000351248	0.006273464
3	120	0.250047	0.000949319	0.028484917
4	210	0.15753	0.002565726	0.084877355
5	252	0.099244	0.006934396	0.173425082
6	210	0.062524	0.01874161	0.24607613
7	120	0.03939	0.050653	0.239425424
8	45	0.024816	0.1369	0.152876368
9	10	0.015634	0.37	0.057845112
10	1	0.009849	1	0.009849303

(a)

(b)

(c)