In: Statistics and Probability
please show the work
It has been suggested that the highest priority of retirees is travel. Thus, a study was conducted to investigate the differences in the length of stay of a trip for pre-and post-retirees. A sample of 697 travelers were asked how long they stayed on a typical trip. The observed results of the study are found below.
number of nights | pre-retirement | post-retirement | total |
4-7 | 241 | 175 | 416 |
8-13 | 78 | 72 | 150 |
14-21 | 30 | 60 | 90 |
22 or more | 11 | 30 | 41 |
total | 360 | 337 | 697 |
With this information construct a table of estimated expected values.
number of nights | pre-retirement | post-retirement |
4-7 | ||
8-13 | ||
14-21 | ||
22 or more |
Now, with that information, determine whether the length of stay is independent of retirement using α=0.01.
(a) Find test value χ2=
(b) Find the d.f.:
(c) Find the critical value:
(d) The final conclusion is
A. There is not sufficient evidence to reject the
null hypothesis that the length of stay is independent of
retirement.
B. We can reject the null hypothesis that the
length of stay is independent of retirement and accept the
alternative hypothesis that the two are dependent.
Expected frequencies will be calculated as follows:
Following table shows the expected frequencies:
Number of Nights | Pre-retirement | Post-retirement | Total |
4-7 | 214.864 | 201.136 | 416 |
8-13 | 77.475 | 72.525 | 150 |
14-21 | 46.485 | 43.515 | 90 |
22 or more | 21.176 | 19.824 | 41 |
Total | 360 | 337 | 697 |
Following table shows the calculations for chi square test statistics:
O | E | (O-E)^2/E |
241 | 214.864 | 3.179176111 |
78 | 77.475 | 0.003557599 |
30 | 46.485 | 5.846084221 |
11 | 21.176 | 4.890015867 |
175 | 201.136 | 3.396162278 |
72 | 72.525 | 0.003800414 |
60 | 43.515 | 6.245093071 |
30 | 19.824 | 5.223515738 |
Total | 28.7874053 |
(a)
So test statistics is:
(b)
Degree of freedom: df =( number of rows -1)*(number of columns-1) = (4-1)*(2-1)=3
(c)
The critical value is : 7.815
(D)
Since so we reject the null hypothesis.
B. We can reject the null hypothesis that the length of stay is independent of retirement and accept the alternative hypothesis that the two are dependent.