Do various occupational groups differ in their diets? A Britishstudy of this question compared 86 drivers and 52 conductors ofLondon double-decker buses. The conductors' jobs require morephysical activity. The article reporting the study gives the dataas \"Mean daily consumption ± (se).\" Some of the studyresults appear below.
| Drivers | Conductors |
|---|
| Total calories |   2820 ± 45   |   2842 ± 46   |
| Alcohol (grams) | 0.23 ± 0.09 | 0.37 ± 0.15 |
What justifies the use of the pooled two-sample ttest?
The similarity of the sample means suggests that the populationstandard deviations are likely to be similar.
The similarity of the sample standard deviations suggests thatthe population standard deviations are likely to bedifferent.    Â
The similarity of the sample means suggests that the populationstandard deviations are likely to be different.The similarity ofthe sample standard deviations suggests that the populationstandard deviations are likely to be similar.
Is there significant evidence at the 5% level that conductorsconsume more calories per day than do drivers? Use the pooledtwo-sample t test to obtain the P-value. (Giveanswers to 3 decimal places.)
