Anonymous
Anonymous asked in Science & MathematicsMathematics · 4 weeks ago

STANDARD DEVIATION MATH HELP?

The average newborn baby weighs 7.9 lbs with standard deviation of approximately 0.5lbs. If this is normal distribution, then what percentage of babies would be more than 9.4 lbs?

2 Answers

Relevance
  • 4 weeks ago

    z = ( x - µ ) / 𝛔

    z = ( 9.4 - 7.9 ) / 0.5

    z = 3

    accumulative p-value from z-score table where z = 3.00.

    From the index table, p = 0.9987 

    ∴ P( X < 7.9 ) =  0.9987 

    ∴ 

    P( X > 7.9 ) = 1 - P( X < 7.9 )

    P( X > 7.9 ) = 1 - 0.9987

    P( X > 7.9 ) = 0.0013 = 0.13%

    • Commenter avatarLogin to reply the answers
  • (9.4 - 7.9) / 0.5 = 1.5/0.5 = 3

    99.7% of data is between -3 and +3 standard deviations from the mean.

    100 - (50 + 99.7/2) =>

    50 - 49.85 =>

    0.15

    0.15% of the babies will be more than 9.4 lbs

    • Commenter avatarLogin to reply the answers
Still have questions? Get your answers by asking now.