Data
To see the raw Data click above on Data!
Graphs
To see Graphs used to summarize this data click above on Graphs!
The Study
I obtained my sample from the sophomore class
of North Olmsted High School by using Minitab to select 30 random
names from the entire list of sophomore students. I only used 30
because the sophomore class only has 330 or so students and the
sample has to be less than 10 percent of the population. So my
sample size would be 30 sophomores and my population is all 330
sophomores. I only received 28 surveys back which is 93 percent
response. The other two will be considered as nonresponse. My survey
I sent out asked, “Do you drink one or more cups of coffee on a
school day?” with answers yes or no.
The type of test used in this study was a 1
proportion z test, because this was a proportion and there was only
one proportion.
1
p = the true proportion of sophomore students at North
Olmsted High School who drink one or more cups of coffee on a school
day
2
Ho: p = .20
3
Ha: p < .20
4
α = 0.05
5
z= (p ̂-.20)/√((.20 (1-.20))/n)
6
Assumptions: 1. Sample is random
2. The population is normal because np = 4
>10 and n(1-p) = 23 > 10.
The sample was too small to say that is a normal sample but,
I will proceed as if it was.
3. 27 < 10% of the population.
7
z = -0.7559
8 p-value = .2248
