We know that the Mean ( or the average ) is 7.7 lbs.The standard deviation : SD = 0.5 lbs.7.7 - 2 * 0.5 = 7.7 - 1 = 6.7 lbsIt means that 6.7 lbs is The Mean - 2 Standard deviations.According to the bell - shaped curve of Normal distribution:50 % + 34 % + 13.5 % = 97.5 %Answer: 97.5 % of babies would be at least 6.7 lbs.
