In: Statistics and Probability
To test Upper H 0 : mu equals20 versus Upper H 1 : mu less than20, a simple random sample of size nequals 19 is obtained from a population that is known to be normally distributed. Answer parts (a)-(d).
(a) If x overbar = 18 and s= 4.2 , compute the test statistic. (Round to two decimal places as needed.)
(b) Draw a t-distribution with the area that represents the P-value shaded. Which of the following graphs shows the correct shaded region?
(c) Approximate the P-value.
(d) If the researcher decides to test this hypothesis at the a= 0.05 level of significance, will the researcher reject the null hypothesis?
Solution: s = 4.2, and the sample size is n = 19.
t= -2.08 b) Area of p-value :
and since p = 0.0263< 0.05, it is concluded that the null
hypothesis is rejected |