Single-Sample f Tests Summer 2017 mportant note: test (and which c sr and which
ID: 3260045 • Letter: S
Question
Single-Sample f Tests Summer 2017 mportant note: test (and which c sr and which critical values) to use. You should choose between the z test and the single- test (and wt iche Consider the information provided earlier in the module before deciding which Consider the in Express the value of the statistic you calculat sample r test. places ed (eg., Zobe or fob) to two decimal Problem S$: Is t rason Nroblcn Sc is it reaabletocoerthat a smpl of 30 scres nandom ith Xobt 70 to be a random sample of scores from a normally distributed population in which -72 and -6.57 Use a two-tailed test with an alpha of.05. 1. 2, 3. What was value of the statistic you calculated? what is the critical value you used for hypothesis testing? ±- What was your decision? lation described- we reject the we conclude that the sample does differ from the popul null hypothesis We conclude that the sample does not differ from the population described-we fail to reject the null hypothesis. Problem 6: Is it reasonable to consider that a sample of 60 scores with Kobt 75 (s 8.5) to be a random sample of scores from a normally distributed population in which -727 Use a two- tailed test with an alpha of.05. (Hint: If you can't find the exact value for the degrees of freedom (d), use the row for the next lower value (e.g., if there is no value for df 55, use the row for df-40). 1. What was the value of the statistic you calculated? (3 decimal 2, what is the critical value you used for hypothesis testing? ± places) What was your decision? 3. We conclude that the sample does differ from the population described- null we reject the e conclude that the sample does not differ from the population described-we fail to reject the null. © Arizona Board of Regents, 2017 All rights reserved 127Explanation / Answer
(question 5) (1)here we use z-test and z=(x--mean)/(sd/sqrt(n))=(70-72)/(6.5/sqrt(30))=-1.68
(2)two-tailed critical value =z(0.05)=1.96
(3) second choice, we conclude that sample mean doesnot differ.........
donot reject H0 as critical value=1.96 is more than absolute value of calculated z=1.68
(question 6)(1) we use t-test and t==(x--mean)/(s/sqrt(n))=(75-72)/(8.5/sqrt(60))=2.73 with n-1=60-1=59 df
(2) two tailed critical t(0.05,59)=2( using ms-excel command=tinv(0.05,59)
(3) first choice, we conclude that the sample does differ...
since critical value=2 is less than calcuated t=2.73