The amounts of nicotine in a certain brand of cigarette are normally distributed with a mean of 0.918 g and a standard deviation of 0.304 g. The company that produces these cigarettes claims that it has now reduced the amount of nicotine. In what range would you expect to find the middle 80% of amounts of nicotine in these cigarettes (assuming the mean has not changed)?
(Enter your answers in ascending order...smaller on left, larger on right. Also, enter your answers accurate to four decimal places.)
If you were to draw samples of size 50 from this population, in what range would you expect to find the middle 80% of most average amounts of nicotine in the cigarettes in the sample?
(Enter your answers in ascending order...smaller on left, larger on
right. Also, enter your answers accurate to four decimal
places.)
The population mean being known, the confidence interval is obtained using a Z-distribution (Gaussian curve) of the mean based on standard deviation.
The critical Z-score for a two-tail 80% confidence level, viz. 0.2 signifiacne level is
The confidence interval is obtained as
For a sample size of 50, we need to consider standard error for mean instead of standard deviation
The confidence interval of sample mean is obtained as
The amounts of nicotine in a certain brand of cigarette are normally distributed with a mean...
The amounts of nicotine in a certain brand of cigarette are normally distributed with a mean of 0.894 g and a standard deviation of 0.302 g. The company that produces these cigarettes claims that it has now reduced the amount of nicotine. In what range would you expect to find the middle 60% of amounts of nicotine in these cigarettes (assuming the mean has not changed)? Between and . (Enter your answers in ascending order...smaller on left, larger on right. Also,...
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(1 point) The nicotine content in cigarettes of a certain brand is normally distributed with mean (in milligrams) u and standard deviation o= 0.1. The brand advertises that the mean nicotine content of their cigarettes is 1.5 mg. Now, suppose a reporter wants to test whether the mean nicotine content is actually higher than advertised. He takes measurements from a SRS of 20 cigarettes of this brand. The sample yields an average of 1.4 mg of nicotine. Conduct a test...
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The nicotine content in cigarettes of a certain brand is Normally distributed with a standard deviation of σ = 0.1 milligrams. The brand advertises that the mean nicotine content of their cigarettes is μ = 1.5, but you are suspicious and plan to investigate the advertised claim by testing the hypotheses H0 : μ = 1.5 versus Ha : μ > 1.5 at the 5% significance level. You will do so by measuring the nicotine content of 15 randomly selected...