Normal Distribution and Significance Level

Math 221
Week 6 Lab

Submitted by: Merima Ceric

Part 1. Normal Distributions and Birth Weights in America

1) What percent of the babies born with each gestation period have a low birth weight (under 5.5 pounds)? a) Under 28 = 99.88% The NORMDIST formula was used to calculate: =NORMDIST(5.5,1.88,1.99,True) X= 5.5 Mean= 1.88 Standard Deviation=1.19

b) 32 to 35 weeks = 43.83% The NORMDIST formula was used to calculate: =NORMDIST (5.5,5.73,1.48,True) X= 5.5 Mean= 5.73 Standard Deviation=1.48

c) 37 to 39 weeks = 4.66% The NORMDIST formula was used to calculate: =NORMDIST(5.5,7.33,1.09, True) X= 5.5 Mean= 7.33 Standard Deviation=1.09

d) 42 weeks and over = 2.75% The NORMDIST formula was used to calculate:=NORMDIST( 5.5, 7.65,1.12, True) X= 5.5 Mean= 7.65 Standard Deviation=1.12

2) Describe the weights of the top 10% of the babies born with each gestation period.

a) 37 to 39 weeks = 8.73 lbs
The NORMINV formula was used to calculate: =NORMINV(0.9,7.33,1.09)
Probability= 0.9
Mean=7.33
Standard Deviation= 1.09 b) 42 weeks and over= 9.09 lbs
The NORMINV formula was used to calculate: =NORMINV(0.9,7.65,1.12)
Probability= 0.9
Mean=7.65
Standard Deviation= 1.12

3) For each gestation period, what is the probability that a baby will weigh between 6 and 9 pounds at birth? a) 32 to 35 weeks = 41.40% The NORMDIST formula was used to calculate: = NORMDIST(9,5.73,1.48,TRUE)-NORMDIST(6,5.73,1.48,TRUE) x= 9 x=6 mean= 5.73 mean = 5.73 standard deviation= 1.48 standard deviation= 1.48

b) 37 to 39 weeks = 82.61% The NORMDIST formula was used to calculate: = NORMDIST(9,7.33,1.09,TRUE)-NORMDIST(6,7.33,1.09,TRUE) x= 9 x=6 mean= 7.33 mean = 7.33 standard deviation= 1.09 standard deviation= 1.09 c) 42 weeks and