What should I buy? A study conducted by a research group in a recent year reported that 57% of cell phone owners used their phones inside a store for guidance on purchasing decisions. A sample of 14 cell phone owners is studied. Round the answers to at least four decimal places. Part 1 of 4 Your Answer is incorrect ( (b) What is the probability that fewer than eight of them used their phones for guidance on purchasing decisions?

answer:
Hence, the probability that seven or more of them used their phones for guidance on purchasing decisions is 0.7887              
Step-by-step explanation:
We are given the following information in the question:
We treat people using phones in the store for guidance  as a success.
P(People use phone for guidance) = 57% = 0.57
Then the number of people follows a binomial distribution, where
Formula:

where n is the total number of observations, x is the number of success, p is the probability of success.
Now, we are given n = 14 and x = 7
We have to evaluate:

Hence, the probability that seven or more of them used their phones for guidance on purchasing decisions is 0.7887