A total of 940 healthy, pregnant women between 20 and 34 years of age participated in a study. Their lengths (in days) of pregnancy are approximately normally distributed (see the normal curve in Fig. 88).

a. Interpret the area of the orange region in Fig. 88 as a probability.
b. Interpret the area of the orange region in Fig. 88 as a proportion.
c. Interpret the area of the orange region in Fig. 88 as a percentile.
d. The researchers defined a preterm delivery as a pregnancy lasting at most 259 days. Women with preterm deliveries were excluded from the study. If these women had been included in the study, how would the mean pregnancy length have been affected? How would the standard deviation have been affected?

Transcribed Image Text:

Lengths of Pregnancy 0.05 270 2809 Days