Question

complete the blanks in the pucture

Exercises (2): Studying the flow of traffic at two busy intersections between 4 P.M. and 6 P.M. (to determine the possible need for turn signals), it was found that on 40 week- days there were on the average 247.3 cars approach- ing the first intersection from the south that made left turns while on 30 weekdays there were on the average 254.1 cars approaching the second intersection from the south that made left turns. The corresponding sam- ple standard deviations are s1 15.2 and s2 = 18.7 (a) Test the null hypothesis u1-2=0 against the alternative hypothe sis u1 -2 0 at the level of significance o 0.01 Complete the blanks for both questions: 1- Null hypothesis: 2- alternative hypothesis: 3- alpha: 4-distribution: 5-rejection of religion (R.R) 6- test: 7-calculation: 8- conclusion:

Answer 1

. Given n,:40 M2 230 - 347-3 7=254.). 5,8 15-2 : 52=18-7 . . , l. Null hypothesis M,-M2=0 .. . 2- Alternate hypothesis sell, M270 3. level of significance 8:001 4. Reject the null hypotheses . 75-2.58 € 77258. . The sample sides nidh, 230, to test the null hypothesis we have the test statistics as

2:..247.3 -254-1 2: -6.8 -1.6286 4.1752. sesesion since 2=-1.6286 does n't Critical regeion The null hypothesis can't be rejected The difference b/w two sample means is not . Significant