REMEMBER WHEN DOING THE ZTEST OR DOING AN A TTEST YOU MUST C

REMEMBER: WHEN DOING THE Z-TEST OR DOING AN A T-TEST. YOU MUST CONSIDER THE MAIN-CRITERIA AND YOU MUST CONSIDER THE SIZE OF THE SAMPLE. WHEN THE SAMPLE SIZE TURNS OUT SMALL (<30) PERFORM A T-TEST, IF THE SAMPLE-SIZE IS LARGER (>= 30) PERFORM A Z-TEST.   SIMILAR WITH TWO-SAMPLE TESTS.

F.QUESTION

Short QUESTIONS AND MULTIPLE CHOICE QUESTIONS:        

confidence interval of 90% USEd to estimate the number# of customers who bought at least two products/items their last store experience. Random sample of a hundred (100) customers producd a confidence interval of: 49% +/- 4%. explain the result?

   TWo(2).Range values of that coefficient of determination wecan take is:

–infinite to + infinite

0% to 100%

-1 to 1

0 to 1

    3. THE regression-equation Y = 200*X – 85.5   shows     a:

          a. positive(+) correlation

          b. strong negative(-) correlation

          c. idoes not show a linear correlation at all.

Solution

1) We are 90% confident that the true proportion is between (49-4=45%) and (49+4=53%)

2) Coefficient of determination is square of correlation coefficient, and varies from 0 to 1 only

3) (c) regression equaltion does not show correlation magnitude, only shows direction (negative)