Calcium is the most abundant mineral in the human body and has several important
ID: 3332359 • Letter: C
Question
Calcium is the most abundant mineral in the human body and has several important functions. Most body calcium is stored in the bones and teeth, where it functions to support their structure. Recommendations for calcium are provided in Deitary Reference Intakes, developed by the Institute of Medicine of the National Academy of Sciences. The recommended adequate intake (RAI) of calcium for adults (19-50) is 1000 milligrams (mg) per day. A simple random sample of 18 adults with incomes below the poverty level gave the following daily calcium intakes.
Data Table Values
886 633 943 847 934 841
1193 820 774 834 1050 1058
1192 975 1313 872 1079 809
a) Identify what procedure (8.1( known) or 8.2 ( unknown)) is used to find this confidence interval. b) Before doing computations, state each assumption and information given/not given to meet each assumption. If all assumptions are met, use StatCrunch to compute the confidence interval. If needed, check if sample is from a normal population using the Shapiro-Wilk normality test in StatCrunch. c) Write the interpretation of the confidence interval.
Explanation / Answer
a) we will use unknown
t-distribution will be used
b)
since p-value > 0.05
normality condition is not violated
Variable N Mean StDev SE Mean 95% CI
C1 18 947.4 172.0 40.5 (861.9, 1032.9)
c) 95% confidence interval is (861.9 , 1032.9)
it means we are 95 % confident that the true mean lies in this confidence interval