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Part B Course Project Math 533 Essay

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Course Project Part B

a. the average (mean) annual income was less than $50,000

Null and Alternative Hypothesis

H0: mu= 50 (in thousands)
Ha: mu<50 (in thousands)

Level of Significance
Level of Significance = .05

Test Statistic, Critical Value, and Decision Rule

Since alpha = .05, z<-1.645, which is lower tailed
Rejection region is, z<-1.645

Calculate test statistic, x-bar=43.74 and s=14.64
Z=(43.74-50)/2.070=-3.024 2.070 is calculated by: s/sq-root of n

Decision Rule: The calculated test statistic of -3.024 does fall in the rejection region of z<-1.645, therefore I would reject the null and say there is sufficient evidence to indicate mu<50.

Interpretation of Results and Conclusion …show more content…

the average (mean) credit balance for suburban customers is more than $4300.
15 people of 50 surveyed live in a suburban community, so I will be conducting a t-test because 15<30.
Null and Alternative Hypothesis
H0: mu=$4,300
Ha: mu>$4,300

Level of Significance

Level of Significance= .05

Test Statistic, Critical Value, and Decision Rule

Since alpha= .05, t>1.761, which is upper tailed.
Rejection region is t>1.761

Calculate the test statistic, x-bar=4675 and s=742
T=(4675-4300)/742sqrt15=1.957

Decision Rule: 1.957 is greater than 1.761, which means it does fall in the rejection region, so I would reject H0. Because I am rejecting H0, this means that there is sufficient evidence to conclude that the average credit balance for the suburban customers is greater than $4300

Interpretation of Results and Conclusion

p-value=.035
.035<.05

Because the p-value of .035 is less than the significance level of .05, I will reject the null hypothesis at 5% level.

95%=(4264, 5086)- I am 95% confident that the average credit balance for suburban customers falls between $4264 and $5,086.

Minitab Output
One-Sample T

Test of mu = 4300 vs > 4300

95% Lower N Mean StDev SE Mean Bound T P
15 4675 742 192 4338 1.96 0.035

Final Report of Results
Before parts a-d are broken down, provided below are a the

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