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7.11 Volunteers who had developed a cold within the previous 24 hours were randomized to take either zinc or placebo lozenges every 2 to 3 hours until their cold symptoms were gone. Twenty-five partici- pants took zinc lozenges, and 23 participants took placebo lozenges. The mean overall duration in days) of symptoms for the zinc lozenges group was 4.5 days, and the standard deviation of overall duration of symptoms was 1.6 days. For the placebo group, the mean overall duration of symptoms was 8.1 days, and the standard deviation of overall duration of symptoms was 1.8 days. Assume that the samples are from independent normal populations. Test whether the population variances are equal or not (use a 10% level of significance). Is it reasonable to conclude that zinc lozenges reduce the overall duration of cold symptoms compared to the placebo group? Use a 5% level of significance.