Many high school students take the AP tests in different subject areas. In 2007, of the
144,796 students who took the biology exam 84,199 of them were
... [Show More] female. In that
same year, of the 211,693 students who took the calculus AB exam 102,598 of them
were female ("AP exam scores," 2013). Estimate the difference in the proportion of
female students taking the biology exam and female students taking the calculus AB
exam using a 90% confidence level.
Given that
n1=144796,n2=211693
90% confidence interval for difference in p1-p2
=(0.5815-0.4847)+/-1.645*sqrt((0.5815*(1-0.5815)/144796)+(0.4847*(1-
0.4847)/211693))
=0.0968+/-0.0028
=(0.0941, 0.0996)
9.1.5
Are there more children diagnosed with Autism Spectrum Disorder (ASD) in states
that have larger urban areas over states that are mostly rural? In the state of
Pennsylvania, a fairly urban state, there are 245 eight year olds diagnosed with ASD
out of 18,440 eight year olds evaluated. In the state of Utah, a fairly rural state, there
are 45 eight year olds diagnosed with ASD out of 2,123 eight year olds evaluated
("Autism and developmental," 2008). Is there enough evidence to show that the
proportion of children diagnosed with ASD in Pennsylvania is more than the
proportion in Utah? Test at the 1% level.
Research Question:
Is there enough evidence to show that the proportion of children diagnosed
with ASD in Pennsylvania is more than the proportion in Utah?
Let p1 = Proportion of children diagnosed with ASD in Pennsylvania
p2 = Proportion of children diagnosed with ASD in Utah
Null hypothesis:
H0: There is no significant difference between the proportion of children
diagnosed with ASD between Pennsylvania and Utah, p1 = p2
Alternative hypothesis:
H1: The proportion of children diagnosed with ASD in Pennsylvania is more
than the porportion of children diagnosed with ASD in Utah, p1 > p2
Level of significance:
Critical Region:
Since, the alternative hypothesis is testing on the one-side(researcher is
interseted if proportion in one group is more than the other) the hypothesis is
tested at one tail. Therefore, form the standard normal table for 1% level of
significance the Z-value is given as 2.33. Therefore, the null hypothesis will be
rejected if the Z-test statistic is more than 2.33
Test statistic:
Where
p1 = Proportion of children diagnosed with ASD in Pennsylvania = 245/18440
= 0.0133
p2 = Proportion of children diagnosed with ASD in Utah = 45/2123 = 0.0212
n1 = Number of children in Pennsylvania = 18440
n2 = Number of children in Utah = 2123
x1 = Number of Children diagnosed with ASD in Pennsylvania = 245
x2 = Number of Children diagnosed with ASD in Utah = 45
Therefore,
Inference:
Since the calculated Z-test staitistic value of -2.9259 is lesser than the Z-critical
value of 2.33, we will not reject the null hypothesis.
Conclusion:
There is no enough evidence to show that the proportion of children
diagnosed with ASD in Pennsylvania is more than the proportion in Utah.
9.2.3
All Fresh Seafood is a wholesale fish company based on the east coast of the U.S.
Catalina Offshore Products is a wholesale fish company based on the west coast of
the U.S. Table #9.2.5 contains prices from both companies for specific fish types
("Seafood online," 2013) ("Buy sushi grade," 2013). Do the data provide enough
evidence to show that a west coast fish wholesaler is more expensive than an east
coast wholesaler? Test at the 5% level. [Show Less]