Answer: 72.78% of the drivers are traveling between 70 and 80 miles per hour based on this distribution.
Step-by-step explanation:
Let X be a random variable that represents the speed of the drivers.
Given: population mean : M = 72 miles ,
Standard deviation: s= 3.2 miles
The probability that the drivers are traveling between 70 and 80 miles per hour based on this distribution:
Hence, 72.78% of the drivers are traveling between 70 and 80 miles per hour based on this distribution.
Answer:
And using the normal standard table or excel we find the probability:
Step-by-step explanation:
Previous concepts
Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".
The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".
Solution to the problem
Let X the random variable that represent the avergae number of weeks an individual is unemployed of a population, and for this case we know the distribution for X is given by:
Where and
Since the distribution for X is normal then, the distribution for the sample mean is given by:
We select a sample of n =50 people. And we want to find the following probability
And using the normal standard table or excel we find the probability: