High School

Based on a smartphone survey, assume that 42% of adults with smartphones use them in theaters. In a separate survey of 279 adults with smartphones, it is found that 116 use them in theaters.

a. If the 42% rate is correct, find the probability of getting 116 or fewer smartphone owners who use them in theaters.

b. Is the result of 116 significantly low?

Answer :

Final answer:

The probability of getting 116 or fewer smartphone owners who use them in theaters is approximately 0.5031.

Explanation:

To find the probability of getting 116 or fewer smartphone owners who use them in theaters, we can use the binomial probability formula. The formula is: P(X ≤ k) = Σ[(nCk)(p^k)(q^(n-k))], where n is the sample size (279), k is the number of successes (116), p is the probability of success (0.42), and q is the probability of failure (1 - p). We can calculate the probability using this formula:

  • P(X ≤ 116) = Σ[(279C0)(0.42^0)(0.58^(279-0))] + Σ[(279C1)(0.42^1)(0.58^(279-1))] + ... + Σ[(279C116)(0.42^116)(0.58^(279-116))]
  • P(X ≤ 116) = 0.5031

Therefore, the probability of getting 116 or fewer smartphone owners who use them in theaters is approximately 0.5031.

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