Question

    You conduct a survey to measure the mean household income for the city of Hays, Kansas. You survey 500 random residents and ask them to report their total household income for 2008. In analyzing the data, you find that the mean annual household income for the sample was $47,300. The standard deviation of this distribution is $9500. What is the 95% confidence interval for the mean annual household income of all residents of Hays?

        $42,578 to $52,377

       $46,467 to $48,133

    $45,225 to $47,746

    $44,775 to $46,464

Question 2

    You conduct a survey to measure the mean household income for the city of Hays, Kansas. You survey 500 random residents and ask them to report their total household income for 2008. In analyzing the data, you find that the mean annual household income for the sample was $47,300. The standard deviation of this distribution is $9500. What is the 99% confidence interval for the mean annual household income of all residents of Hays?

       $45,002 to 47,093

    $45,364 to $47,385

    $45,805 to $47,888

    $46,208 to $48,392

Answer 1

given data are:-

a). z critical value for 95% confidence level, both tailed test be:-

the 95% confidence interval for the mean annual household income of all residents of Hays be:-

=   $46,467 to $48,133

b). z critical value for 99% confidence level, both tailed test be:-

the 99% confidence interval for the mean annual household income of all residents of Hays be:-

~ $46208 to $48392 [ as this is the nearest option]

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