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JAI ., MEMORANDUM June 7, 1977 HOW FAR DO SMOKERS STICK CIGARETTES IN THEIR MOUTHS? By Jean Myers, D. W. Shewmaker, F. J. Schultz and W. C. Thompson . Introduction With the advent of air dilution filters on cigarettes, the depth of insertion of test cigarettes in a smoking machine has come under close scrutiny. An insertion of 11 mm. has been standard but this causes interference with certain filters by inhibiting the amount of air dilution which increases the amount of "tar" and nicotine delivery. Summary A survey of 141 cigarette smokers indicates that the average depth of insertion of a cigarette into the mouth is 7.5 mm. (95% confidence limits for the population mean are from 7.2 to 7.9 mm.). The distribution of insertion depths is positively skewed which results in the median being slightly lower than the mean. The median insertion depth was found to be 7.4 mm. (95% confidence limits for the population median are from 7.0 to 7.9 mm.). These data indicate that an insertion of 7 mm. in a smoking machine is appropriate for "tar" and nicotine assay. Experimental Lacking any previously published data, we conducted a study among Lorillard employees at both the Greensboro, North Carolina, and Louisville, Kentucky, locations. Subjects were obtained from the Greensboro Plant offices, the Louisville Plant offices and the Research Center. A sample of 82 men and 59 women were observed. A preliminary study showed that asking a person to smoke so that a measurement could be made resulted in grossly atypical behavior and, consequently, biased results. Therefore, the method employed to collect the data was to have an observer find persons smoking at their leisure, then as they were taking a puff, the observer asked them to stop, marked the butt at the point of maximum lip p W

C -2- C contact and measured the distance from the mark to the butt end of the cigarette. The data obtained are shown in the attached Table 1. Discussion Analysis of the data reveals that there are no significant effects of sex or location of survey on the depth of cigarette insertion. The close agreement of the data taken by two experimenters at widely separated locations lends credence to the tacit assumption that the sample of smokers is representative of the whole population. A histogram of the experimental data is shown in Figure 1. This histogram shows that the data distribution is positively skewed and slightly but distinctly non-normal. The skew in the data is not unexpected. There are limits to the low values of insertion. There is an absolute limit of zero;negative insertion values have no meaning. There is also some poorly defined lower limit to insertion values below which the cigarette will fall out of the mouth. In contrast, the upper limit of insertion value is the total length of the cigarette. This non-symmetry of limits tends to produce skewed distributions like the one observed. While the skewness of the distribution can be explained, it does present a problem of which measure of central tendency to use to characterize the data. The mean is the most commonly used measure of central tendency but it is inordinately influenced by the very high values observed. The median, or 50th percentile of the population, is a viable alternate measure of central tendency for skewed distributions. The percentiles of insertion depth for the population are estimated in Table 2 and shown graphically in Figure 2. The mean insertion depth for the population was calculated in Table 1. The parameters are shown below: Estimate 95% Confidence Limits Mean 7.5 mm. 7.2 to 7.9 mm. 50th-Percentile (Median) 7.4 mm. 7.0 to 7.9 mm. These data indicate that an insertion of 7 mm. in a smoking machine will closely approximate the typical smoker and is, therefore, appropriate for "tar" and nicotine assay.

TABLE 1 EXPERIMENTAL DATA FREQUENCY OF OBSERVATION INSERTION GREENSBORO LOUISVILLE MM. MALE FEMA LE MALE FEMALE TOTAL 3 0 1 0 1 2 4 3 0 0 0 3 4.5 2 0 - - 2 5 5 2 4 3 14 5.5 3 0 - - 3 6 4 5 3 9 21 6.5 0 3 - - 3 7 9 2 6 5 22 7.5 4 3 - - 7 8 6 3 8 9 26 8.5 3 2 - - 5 9 3 2 3 3 11 9.5 1 0 - - 1 10 6 1 1 1 9 11 3 0 1 1 5 12 0 1 0 1 2 12.5 1 0 - - 1 13 1 0 1 0 2 14 1 1 0 0 2 TOTAL 55 26 27 33 141 Average, x 7.672 7.462 7.592 7.242 Std. Dev.,,a- 2.336 2.222 1.866 1.820 95% C.L. X± 0.631 R± 0.896 x± 0.737 x ± 0.644 x MALE FEMALE GREENSBORO LOUISVILLE n . .82 59 81 60 Average, x 7.646 7.339 7.605 7.400 Std. Dev.,A. 2.181 1.992 2.288 1.834 95% C.L. x± 0.479 x± 0.519 x± 0.506 K ± 0.474 7.518 2.102 ± 0.350 «

c TABLE 2 PERCENTILES OF INSERTION DEPTH INSERT ION FREQUE NCY RANKS AVERAGE RANK % LCL UCL 3 mm. 2 1 - 2 1.5 1.0 0.1 - 4.6 4 3 3 - 5 4 2.8 0.8 , 7.2 4.5 2 6 - 7 6.5 4.6 1.8 9.6 5 14 8 - 21 14.5 10.2 4.0 16.7 5.5 3 22 - 24 23 16.2 8.8 23.5 6 21 25 - 45 35 24.6 16.0 32.7 6.5 3 46 - 48 47 33.1 23.6 41.6 7 22 49 - 70 59.5 41.9 31.8 50.5 7.5 7 71 - 77 74 52.1 41.6 60.5 8 26 78 - 103 90.5 63.7 53.2 71.5 8.5 .5 104 - 108 ,,106 74.6 64.6 81.4 9 11 109 - 119 114 80.3 70.6 86.3 9.5 1 120 120 84.5 75.3 89.8 10 9 121 - 129 125 88.0 79.3 92.6 11 5 130 - 134 132 93.0 87.0 96.6 12 2 135 - 136 135.5 95.4 90.4 98.2 12.5 1 137 137 96.5 91.8 98.9 13 2 138 - 139 138.5 97.5 93.3 99.4 14 2 140 - 141 140.5 98.9 95.4 99.9 141

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