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the mean cost of domestic airfares in the united states rose to an all-time high of $385 per ticket. airfares were based on the total ticket value, which consisted of the price charged by the airline plus any additional taxes and fees. assume domestic airfares are normally distributed with a standard deviation of $110. answer to four decimals. what is the probability domestic airfare is $250 or less.

Respuesta :

The probability 11.1% of domestic airfares within the United States are $250 or less.

Define the term standard deviation?

  • A square root of variance is used to calculate the standard deviation, a statistic that illustrates how distributed widely a dataset is in relation to its mean.
  • By evaluating the deviation of each data point from the mean, the standard deviation may be approximated as the square root of variance.

The formula for the z score is -

z = (x - μ)/σ

In which,

  • μ = mean = $385 per ticket
  • σ = standard deviation = $110
  • x = sample value = $250 or less.

Substitute the value in formula.

P(x ≤ 250) = (250 - 385)/100

P(x ≤ 250) = -1.22

Select the p value from negative z score table;

P(x ≤ 250) = 0.111

P(x ≤ 250) = 11.1%

Thus, 11.1% of domestic flights within the United States are $250 or less.

To know more about the standard deviation, here

https://brainly.com/question/475676

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