Final answer:
To determine the probabilities of different incomes in Martin county, calculate the z-scores and use the standard normal distribution to find the required likelihoods.
Step-by-step explanation:
To find the probability that a randomly selected Martin county household has an income greater than or equal to $50,468, we must first calculate the z-score which is the number of standard deviations away from the mean the value $50,468 is. The formula for the z-score is Z = (X - μ) / σ, where X is the value in question, μ is the mean, and σ is the standard deviation. After finding the z-score, we can use the standard normal distribution table to find the probability that a z-score is greater than or equal to the calculated z-score.
To calculate the probability that a randomly selected household has an income between $45,128 and $51,264, we again calculate the z-scores for both values and then find the probability that the z-score falls between these two values using the standard normal distribution.