Show all your work for credit Solve the problemsl3 by answer
Solution
a)
Male and female high school students have equal mean ACT scores. [ANSWER]
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b)
Let
u1 = mean of male
u2 = mean of female
Formulating the null and alternative hypotheses,
Ho: u1 - u2 = 0
Ha: u1 - u2 =/ 0 [ANSWER]
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c)
At level of significance = 0.01
A
s we can see, this is a two tailed test.
Calculating the means of each group,
X1 = 21.2
X2 = 20.9
Calculating the standard deviations of each group,
s1 = 4.9
s2 = 4.6
Thus, the standard error of their difference is, by using sD = sqrt(s1^2/n1 + s2^2/n2):
n1 = sample size of group 1 = 43
n2 = sample size of group 2 = 56
Thus,
sD = 0.967589394
Thus, the z statistic will be
z = [X1 - X2 - uD]/sD = 0.310048872 [ANSWER]
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d)
where uD = hypothesized difference = 0
Now, the critical value for z is
zcrit = +/- 2.576 [ANSWER]
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e)
As |z| < 2.576, WE FAIL TO REJECT THE NULL HYPOTHESIS.
Thus, there is no significant evidence taht the mean scores of female and male high school students in ACT are different at 0.01 level. [CONCLUSION]

