Answer:
0.7392 = 73.92% probability of obtaining a value less than 45 or greater than 49.
Step-by-step explanation:
Normal Probability Distribution
Problems of normal distributions can be solved using the z-score formula.
In a set with mean and standard deviation
, the z-score of a measure X is given by:
The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.
Mean 47 and standard deviation 6
This means that
Less than 45:
p-value of Z when X = 45, so:
has a p-value of 0.3696.
More than 49:
1 subtracted by the p-value of Z when X = 49. So
has a p-value of 0.6304.
1 - 0.6304 = 0.3996
Less than 45 or greater than 49:
2*0.3696 = 0.7392
0.7392 = 73.92% probability of obtaining a value less than 45 or greater than 49.