In: Statistics and Probability
Is there a difference between the means of the total of rooms per hotel in Crete and Southern Aegean Islands? Answer your question by calculating an appropriate, symmetric, 95% confidence interval using a Z statistic and equal standard deviations in the two populations. Explain your findings
REGION ID
1= Crete
2=Southern Aegean Islands
3=Ionian Islands
| Total_Rooms | Region_ID |
| 412 | 1 |
| 313 | 1 |
| 265 | 1 |
| 204 | 1 |
| 172 | 1 |
| 133 | 1 |
| 127 | 1 |
| 322 | 1 |
| 241 | 1 |
| 172 | 1 |
| 121 | 1 |
| 70 | 1 |
| 65 | 1 |
| 93 | 1 |
| 75 | 1 |
| 69 | 1 |
| 66 | 1 |
| 54 | 1 |
| 68 | 1 |
| 57 | 1 |
| 38 | 1 |
| 27 | 1 |
| 47 | 1 |
| 32 | 1 |
| 27 | 1 |
| 48 | 1 |
| 39 | 1 |
| 35 | 1 |
| 23 | 1 |
| 25 | 1 |
| 10 | 1 |
| 18 | 1 |
| 17 | 1 |
| 29 | 1 |
| 21 | 1 |
| 23 | 1 |
| 15 | 1 |
| 8 | 1 |
| 20 | 1 |
| 11 | 1 |
| 15 | 1 |
| 18 | 1 |
| 23 | 1 |
| 10 | 1 |
| 26 | 1 |
| 306 | 2 |
| 240 | 2 |
| 330 | 2 |
| 139 | 2 |
| 353 | 2 |
| 324 | 2 |
| 276 | 2 |
| 221 | 2 |
| 200 | 2 |
| 117 | 2 |
| 170 | 2 |
| 122 | 2 |
| 57 | 2 |
| 62 | 2 |
| 98 | 2 |
| 75 | 2 |
| 62 | 2 |
| 50 | 2 |
| 27 | 2 |
| 44 | 2 |
| 33 | 2 |
| 25 | 2 |
| 42 | 2 |
| 30 | 2 |
| 44 | 2 |
| 10 | 2 |
| 18 | 2 |
| 18 | 2 |
| 73 | 2 |
| 21 | 2 |
| 22 | 2 |
| 25 | 2 |
| 25 | 2 |
| 31 | 2 |
| 16 | 2 |
| 15 | 2 |
| 12 | 2 |
| 11 | 2 |
| 16 | 2 |
| 22 | 2 |
| 12 | 2 |
| 34 | 2 |
| 37 | 2 |
| 25 | 2 |
| 10 | 2 |
| 270 | 3 |
| 261 | 3 |
| 219 | 3 |
| 280 | 3 |
| 378 | 3 |
| 181 | 3 |
| 166 | 3 |
| 119 | 3 |
| 174 | 3 |
| 124 | 3 |
| 112 | 3 |
| 227 | 3 |
| 161 | 3 |
| 216 | 3 |
| 102 | 3 |
| 96 | 3 |
| 97 | 3 |
| 56 | 3 |
| 72 | 3 |
| 62 | 3 |
| 78 | 3 |
| 74 | 3 |
| 33 | 3 |
| 30 | 3 |
| 39 | 3 |
| 32 | 3 |
| 25 | 3 |
| 41 | 3 |
| 24 | 3 |
| 49 | 3 |
| 43 | 3 |
| 9 | 3 |
| 20 | 3 |
| 32 | 3 |
| 14 | 3 |
| 14 | 3 |
| 13 | 3 |
| 13 | 3 |
| 53 | 3 |
| 11 | 3 |
| 16 | 3 |
| 21 | 3 |
| 21 | 3 |
| 46 | 3 |
| 21 | 3 |
Sol:
| Descriptive statistics | ||
| Region1_Total_Rooms | Region2_Total_Rooms | |
| Mean | 82.31111111 | 86.66666667 |
| Variance | 9202.219192 | 10119.77273 |
| Observations | 45 | 45 |
| Pooled Variance | 9660.99596 | |
Null hypothesis
Ho:
Ha:
alpha=0.05
Sp=pooled standard deviation
=sqrt((n1-1)*s1^2+(n2-1)*s2^2/(n1+n2-2)
=sqrt(45-1)*9202.219192+(45-1)*10119.77273/(45+45-2))
=98.29037
95% confidence interval for difference in means assuming equal variances is
(x1bar-x2bar)+-Z*Sp*sqrt(1/n1+1/n2)
=(82.3111-86.6667)+-1.96*98.29037*sqrt(1/45+1/45)
=-4.356+-1.96*98.29037*sqrt((1/45+1/45))
=-4.356+-40.614
=-4.356-40.614,-4.356+40.614
=-44.97,36.26
This confidence interval contains 0
Fail to reject Ho
Accept Ho
Conlclusion:
There is no sufficient statistical evidence by 95% confidence interval that
there is a difference between the means of the total of rooms per hotel in Crete and Southern Aegean Islands.