91影视

Let $X=$ the number of owners who greet their dogs first.

Binary (success/failure), independent trials, a fixed number of trials, and the equal probability of success for each trial are the four conditions for a binomial setting.

Success = greeting the dog first; failure = not greeting the dog first.

Because the dog owners were chosen at random, they are independent.

Fixed number of trials: $12$.

Probability of success: $66\%$or $0.66$.

Thus all $4$conditions have been met, which means that $X$is a binomial random variables.

Let $X=$ the number of owners greet their dogs first.

$n=12$

$p=66\%=0.66$

Definition binomial probability:

localid="1650079286605" $$\begin{gathered} P(X鈮�4)=P(X=0)+P(X=1)+P(X=2)+P(X=3)+P(X=4) \\ =0.0213 \\ 鈮�2.13\% \end{gathered}$$

Command Ti83-Ti84 calculator: binomcdf $(12,0.66,4)$.

Since the probability is less than $5\%$, there is convincing evidence against the Ladies Home Journal claim.