Q. variable with mean 29 and standard deviation 25. What is the probability that X is between 4 and 54?
Convert to Z-scores: First, we need to convert the X values to Z-scores.Z=standard deviation(X−mean)
Calculate Z-score for X=4: Calculate the Z-score for X=4.Z=254−29Z=−1
Calculate Z-score for X=54: Calculate the Z-score for X=54.Z=2554−29Z=1
Look up in Z-table: Now, we look up the Z-scores in the standard normal distribution table.The probability for Z=−1 is approximately 0.1587.The probability for Z=1 is approximately 0.8413.
Find probability between 4 and 54: To find the probability that X is between 4 and 54, subtract the smaller probability from the larger one.Probability(X is between 4 and 54) = P(Z<1)−P(Z<−1)Probability(X is between 4 and 54) = 0.8413−0.1587Probability(X is between 4 and 54) = 0.6826