Question

based on a smartphone survey assume that 60% of adults with smartphones use them in theaters. in a separate survey of 206 adults with smartphones, it is found that 123 use them in theaters. a. if the 60% rate is correct find the probability of getting 123 or fewer smartphone owners who use them in theaters. b. is the result if 123 significantly low?

Answer 1

a)

here mean of distribution=μ=np=		123.6
and standard deviation σ=sqrt(np(1-p))=		7.0314
for normal distribution z score =(X-μ)/σx
therefore from normal approximation of binomial distribution and continuity correction:

probability of getting 123 or fewer smartphone owners who use them in theaters :

probability =

P(X<123.5)

=

P(Z<-0.01)=

0.4960

b)

No as this is greater than 0.05 , therefore result of 123 is not significantly low .