Question

A researcher predicts that smoking cigarettes decreases a person's sense of smell. on a test of olfactory sensitivity, the mew for non-smokers is 18.4. A sample of people who smoke a pack a day produces these scores
16, 14, 19, 17, 16, 18, 17, 15, 18, 19, 12, 14

Answer 1

One-Sample T: Data

Descriptive Statistics

N	Mean	StDev
12	16.250	2.179

μ: mean of Data

Test

Null hypothesis	H₀: μ = 18.4
Alternative hypothesis	H₁: μ < 18.4

test statistic t =  

df = n-1 = 11

alpha = 0.05

t critical = -t0.05,11  = -1.796

T-Value	P-Value
-3.42	0.003

Since p-value is less than alpha we reject H0 and there is sufficient evidence to conclude that smoking cigarettes decreases a person's sense of smell.