Answer:
10.224 < μ < 12.622 ;
Since the mean weight of 2-montj old baby boys (13.9) falls outside the confidence interval, we can conclude that it is not reasonable to believe that the mean weight of two-month-old baby girls may be the same as that of two-month-old baby boys.
Explanation:
The confidence interval is given as :
Mean ± Margin of Error
margin of error = Zcritical * standard deviation /sqrt(n)
n = sample size
From the data:
12.32, 11.87, 12.34, 11.48, 12.66, 8.51, 14.13, 12.95, 9.34, 8.63
From the data:
Using calculator :
Mean, = 11.423
Standard deviation, s = 1.934
Zcritical at 95% confidence interval = 1.96
Sample size, n = 10
Margin of Error = 1.96* 1.934/sqrt(10) = 1.199
Lower boundary = 11.423 - 1.199 = 10.224
Upper boundary = 11.423 + 1.199 = 12.622
10.224 < μ < 12.622
Since the mean weight of 2-montj old baby boys (13.9) falls outside the confidence interval, we can conclude that it is not reasonable to believe that the mean weight of two-month-old baby girls may be the same as that of two-month-old baby boys.