The percentage of women in the united states will wear a size 6 fits or smaller is 22.07%.
The z score is used to determine by how many standard deviations, the raw score is above or below the mean. It is given by:
z = (x - μ)/σ
where x is raw score, μ is mean and σ is standard deviation.
μ = 23.4, σ = 1.3, x = 6 fits = 22.4, hence:
For x < 22.4:
z = (22.4 - 23.4)/1.3 = -0.77
P(z < -0.77) = 0.2207
The percentage of women in the united states will wear a size 6 fits or smaller is 22.07%.
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