Half of a number decreased by 8 is 3
1 answer:
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Fun. I prefer Oxymetazoline.
For the control group we have a headache probability of
c = 368/1671 = .220
For the experimental group we have a headache probability of
e = 494/2013 = .245
The observed difference is
d = e - c = .025
The variance of the difference is
s² = c(1-c)/n₁ + e(1-e)/n₂
so the standard deviation is
We get a t statistic on the difference of
t = d/s = .025/.0139 = 1.79
We're interested in the one sided test, P(d > 0). We have enough dfs to assume normality. We look up in the standard normal table
P(z < 1.79) = .96327
so
p = P(z > 1.79) = 1 - .96327 = 0.037 = 3.7%
Answer: That's less that 10% so we have evidence to conclude that headaches are significantly greater in the experimental group.
Answer:
7, 10 and 15
Step-by-step explanation:
Given
--- Students already enrolled
Required
Determine the additional number of students needed for the teacher not to cancel the class
First, we need to calculate the number of students for the teacher to cancel the class.
Represent this with x.
So, we have:
Make x the subject
Substitute values for Total and S1
This means that if less than 7 additional students come to the class, the teacher will cancel the class.
So, for the teacher not to cancel the class, the students must be 7 or greater (i.e. 7, 8, 9, 10....)