Complete the statement. Round your answer to the nearest thousandth.In a population that is normally distributed with mean 98 and standard deviation 13, the bottom 90% of the values are those less than ___.
Q. Complete the statement. Round your answer to the nearest thousandth.In a population that is normally distributed with mean 98 and standard deviation 13, the bottom 90% of the values are those less than ___.
Find z-score: We need to find the z-score that corresponds to the bottom 90% of a normal distribution.
Use z-table: Using a z-table, we find that the z-score for the bottom 90% is approximately 1.28.
Apply z-score formula: Now we use the z-score formula: z=standard deviationX−mean. We need to solve for X, which represents the value we're looking for.
Rearrange formula: Rearrange the formula to solve for X: X=z×standard deviation+mean.
Plug in values: Plug in the values: X=1.28×13+98.
Calculate X: Calculate the value of X: X=16.64+98.
Correct z-score:X=114.64, but we made a mistake, the z-score for the bottom 90% is not 1.28, it's actually −1.28 because we are looking for the value below the mean, not above it.
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