The number of potholes in any given 1 mile stretch of freeway pavement in Pennsylvania has a bell-shaped distribution. This distribution has a mean of 42 and a standard deviation of 10. Using the empirical rule, what is the approximate percentage of 1-mile long roads with potholes numbering between 32 and 72

Respuesta :

Answer:

you fool

Step-by-step explanation:This would be easier to show on a graph but I don't think that's possible here so I'll do my best to explain.

The empirical rule states for a normal distribution:

68% of the data are within ± 1 standard deviation from the mean

95% of the data are within ± 2 standard deviations from the mean

99.7% of the data are within ± 3 standard deviations from the mean

A normal distribution is also symmetric around its mean. Since that's the case, 34% (1/2 of 68) would be within +1 standard deviation from the mean and 34% would be within -1 standard deviation from the mean

This problem asks what is the percentage between 53 and 65 when the mean is 62 and the standard deviation is 3. Putting this in terms of the mean and standard deviations, this problem asks what is the percentage between -3 and + 1 standard deviations?

The percentage between the mean and -3 standard deviations is 49.85% (this is one half of 99.7%)

The percentage between the mean and +1 standard deviations is 34% (one half of 68%)

Add those two together to get your total percentage

There is a probability of 84% that there are 1-mile long roads with potholes numbering between 32 and 72

What is z score?

The z score is used to determine by how many standard deviations the raw score is above or below the mean. It is given by:

z = (raw score - mean)/standard deviation

Given that:

mean of 42 and a standard deviation of 10, For:

For x = 32:

z = (32 - 42) / 10 = -1

For x = 72:

z = (72 - 42) / 10 = 3

P(-1 < z < 3) = P(z < 3) - P(z < -1) = 0.9987 - 0.1587 = 0.84

There is a probability of 84% that there are 1-mile long roads with potholes numbering between 32 and 72

Find out more on z score at: https://brainly.com/question/25638875