Question

In part of an agreement between cigarette agencies and the government, levels of nicotine in cigarettes are to be slowly reduced over time. A sample of 40 measurements conducted on one brad of cigarettes 10 years ago yielded an average of 32.9mg per cigarette with a sample standard deviation of 4.4 mg. A study done last month on 30 cigarettes of this brand yielded a sample mean of 30.6mg with sample standard deviation 5.1 mg. What type of test should be used to determine if the levels now are lower than what they were 10 years ago

Answer 1

Answer: INDEPENDENT SAMPLES T-TEST

Explanation:

Given that;

sample size n₁ = 40, sample size n₂ = 40

sample mean x₁ = 32.9, sample mean x₂ = 30.6

Standard deviation S₁ = 4.4, Standard deviation S₂ = 5.1

Now

NULL hypothesis H₀ : u₁ = u₂

and Alternative hypothesis H₁ : u₁ > u₂

Therefore based on the information provided above, the type of test that should be used to determine whether the level of nicotine are now lower than what they were 10 years ago is the INDEPENDENT SAMPLES T-TEST