The recommended amount of iron intake for healthy teenage females is 15 mg per day. A random sample of 1,500 teenage females across the US had their iron intake tested. The mean of the sample was 14.9 mg, with a standard deviation of 2.8 mg. Is there statistically significant evidence at the Alpha = 0.05 level to conclude that US teen females have a lower mean iron intake than recommended? Let Mu = the true mean amount of daily iron intake among teenage females.
Null hypothesis: mu = 15 mg per day
Alternative hypothesis: mu less-than 15 mg per day
Use a graphing calculator to determine the test statistic and P-value of this test.
Round both values to 3 decimal places.
Test statistic: t =
P-value: