Pls help will give Brainlyist

Mathematics

1 answer:

kvasek [131]3 years ago

7 0

Answer:

Step-by-step explanation:

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What should I buy? A study conducted by a research group in a recent year reported that 57% of cell phone owners used their phon

vovangra [49]

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:

$P(X=x) = \binom{n}{x}.p^x.(1-p)^{n-x}$

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:

$P(x \geq 7) = P(x = 7) + P(x = 8) + P(x = 9) + P(x = 10) + P(x =11) + P(x = 12) + P(x = 13) + P(x = 14)\\= \binom{14}{7}(0.57)^7(1-0.57)^7 + \binom{14}{8}(0.57)^8(1-0.57)^6 + \binom{14}{7}(0.57)^9(1-0.57)^5 + \binom{14}{7}(0.57)^{10}(1-0.57)^4 + \binom{14}{7}(0.57)^{11}(1-0.79)^3 + \binom{14}{7}(0.57)^{12}(1-0.57)^2 + \binom{14}{7}(0.57)^{13}(1-0.57)^1 + \binom{14}{7}(0.57)^{14}(1-0.57)^0\\= 0.7887 = 78.67\%$