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    Z score and T test

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    Z test
    At a retail store, customer survey is South Dallas the average household income of 75 household showed $90K with standard deviation of $25K. At another store in North Dallas, the household income of 60 households surveyed showed $120K with standard deviation of $30K. At significance level of 0.07, can a research analyst conclude that population means are different?

    T test
    A random sample of 20 car loans in Ben's finance shows household income of $95K with standard deviation of $18K. A random sample at Citi-Finance of 15 car loans showed household income of $105K with standard deviation of $16K. At significance level of .10, is there a difference in the population means? What inferences could you draw from this test?

    need to show breakdown of answer(s).

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    https://brainmass.com/statistics/students-t-test/score-test-224532

    Solution Preview

    Please see the attachments for explanations.

    Answer
    H0: There is no significant difference in the average house hold income in the two cities.
    H1: There is significant difference in the average house hold income in the two cities.
    The test statistic used is
    Significance level  =0.07
    Decision rule: Reject the null hypothesis if the calculated value of Z is greater than the critical value of Z.
    Details
    Z Test for Differences in Two Means

    Data
    Hypothesized Difference 0
    Level of Significance 0.07
    Population 1 Sample : South Dallas
    Sample Size 75
    Sample Mean 90
    Population Standard Deviation 25
    Population 2 Sample : North Dallas
    Sample ...

    Solution Summary

    The solution provides step by step method for the calculation of Z score and probability. Formula for the calculation and Interpretations of the results are also included.

    $2.19

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