Write your answer to at least 3 decimal places if appropriate, unless it is specified otherwise. 1. Let u be the mean level of Selenium in the blood for elderly people (in units mg/dL). It is of interest to know whether these mean levels have changed over time from the historical value of Selenium. It is claimed that due to a change in diet, the mean level of Selenium in the blood for elderly people (in units mg/dL), H, is no longer equal to 19.6 but has increased. Let X denote the level of Selenium in the blood of a random selected elderly person. A random sample of Selenium from n = 21 individuals is taken from the population of elderly people. The following summary statistics are obtained from the sample: n sample mean sample sd 21 22.1889 4.225254 We can assume each observation is independent and identically distributed N (u,0%). Carry out a one-sample t-test : and complete the exercises below. In this question, t(4) = t4, at distribution with 4 degrees of freedom. (a) Select the null distribution of the test statistic. That is, the distribution of the test statistic assuming He is true.
a)t(20)
b)N (0,1)
c)t(10)
d)t(21)
e) t(22)
(b) Compute the observed value of the test statistic for this hypothesis test. Write your answer to at least 3 decimal places. (c) P-value for this hypothesis test lies in which of the following interval? (0.1,1) 0(0.05, 0.1) (0.025, 0.05) O(0.01, 0.025) 0(0, 0.01)
