Question

Based on a smartphone​ survey, assume that 49​% of adults with smartphones use them in theaters. In a separate survey of 216 adults with​ smartphones, it is found that 90 use them in theaters. a. If the 49​% rate is​ correct, find the probability of getting 90 or fewer smartphone owners who use them in theaters. b. Is the result of 90 significantly​ low? a. If the 49​% rate is​ correct, the probability of getting 90 or fewer smartphone owners who use them in theaters is

Answer 1

n=	216	p=	0.4900
here mean of distribution=μ=np=		105.84
and standard deviation σ=sqrt(np(1-p))=		7.3470
for normal distribution z score =(X-μ)/σx

a)

probability of getting 90 or fewer smartphone owners who use them in theaters:

probability =

P(X<90.5)

=

P(Z<-2.09)=

0.0183

( please try 0.0154 if above comes wrong due to continuity correction and revert)

b)

Yes as probability of having  90 or fewer smartphone owners who use them in theaters is less then 0.05