# A certain standardized​ test's math scores have a​ bell-shaped distribution with a mean of 520 and a standard deviation of 119.What percentage of standardized test scores is less than 401 or greater than 639​?

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A certain standardized​ test's math scores have a​ bell-shaped distribution with a mean of 520 and a standard deviation of 119.

What percentage of standardized test scores is less than 401 or greater than 639​?

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Step 1

Given Data

Mean = 520

Standard Deviation = 119

Percentage of test scores less than 401 is given by help_outlineImage TranscriptionclosePercentage of test scores less than 401 is given by 401 520 _ P(X 401) P 119 0.1587 (From Excel NORM.S. DIST (-1, TRUE)) P(Z <1) Percentage of test scores greater than 639 is given by 639 520 P(X639) P 119 P(Z > 1) 1- P(Z < 1) 1 - 0.8413 = 0.1587 NORM.S. DIST (1, TRUE)) (From Excel fullscreen
Step 2

Percentage of standardized test scores is less than ... help_outlineImage Transcriptionclose= Percentage of test scores less than 401 Percentage of test scores greater than 639 = 0.1587 0.1587 = 0.3174 0.32 Percentage 0.32 X 100 32% fullscreen

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