The mean weight gain during pregnancy is 30 pounds with a standard deviation of 12.9 pounds. If an obstetrician obtains a random sample of 35 patients, what is the probability that the mean weight gain during pregnancy from that sample is at least 34.5 pounds?
That is, with n = 35, what is P(x≥34.5)?
Solution :
Given that,
mean = = 30
standard deviation = =12.9
n=35
= =30
= / n = 12.9 / 30 = 2.3552
P(x≥34.5) = 1 - P( <34.5 )
= 1 - P[( - ) / < (34.5-30) /2.3552 ]
= 1 - P(z <1.91 )
Using z table
= 1 - 0.9719
= 0.0281
probability= 0.0281
The mean weight gain during pregnancy is 30 pounds with a standard deviation of 12.9 pounds....
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