Answer:
There is sufficient statistical evidence in the sample to state that the average tar content in filter cigarettes is less than 21.1.
Step-by-step explanation:
To solve this problem, we run a hypothesis test about the population mean. Consider the average tar content in filter cigarettes.
Mean in the null hypothesis (Mo) =
Sample size (n) = 25
Sample mean (X) = 19.6
Sample standard deviation (S) = 3.68
Significance level = 0.05
H0: Mo = 21.1
Ha: Mo = <21.1
Test statistic = [tex]\frac{(X - Mo)\sqrt{n}}{s}[/tex]
Left critical T value (for 0.05) = -1.7109
Calculated statistic = [tex]\frac{(19.6 - 21.1)\sqrt{25}}{3.68}[/tex] = -2.0380
Since, the value of the test statistic is less than the value of the calculated statistic, the null hypothesis is rejected. There is sufficient statistical evidence in the sample to state that the average tar content in filter cigarettes is less than 21.1.