NEED NOW PLEASE

    Question 9

    The mean IQ score of a sample of 54 students selected from a high school is 89. Suppose the standard deviation of IQ’s at this school is ? = 8.6. The 99% confidence interval for the population mean (rounded to two decimal places) is:

    The lower limit is 

    The upper limit is 

    Question 2

    A sample of size 118 from a population having standard deviation ? = 9 produced a mean of 42. The 99% confidence interval for the population mean (rounded to two decimal places) is:

    The lower limit is 

    The upper limit is 

    Question 3

    The mean federal income tax paid last year by a random sample of 35 persons selected from a city was $4311. Suppose the standard deviation of tax paid in this city is ? = $898. The 95% confidence interval for the population mean (rounded to two decimal places) is:

    The lower limit is $

    The upper limit is $

    Question 8

    A random sample of 96 customers, who visited a department store, spent an average of $75 at this store. Suppose the standard deviation of expenditures at this store is ? = $16. The 98% confidence interval for the population mean (rounded to two decimal places) is:

    The lower limit is $

    The upper limit is $

      

                                                                                                                                      Order Now